diff --git a/.gitattributes b/.gitattributes
index 5e686cf4..f8866dbb 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,5 +1,6 @@
 /.github/               export-ignore
 /tests/                 export-ignore
+/tools/                 export-ignore
 /.editorconfig          export-ignore
 /.gitattributes         export-ignore
 /.gitignore             export-ignore
diff --git a/.github/CONTRIBUTING.md b/.github/CONTRIBUTING.md
index 1b95c247..d4b7c782 100644
--- a/.github/CONTRIBUTING.md
+++ b/.github/CONTRIBUTING.md
@@ -11,6 +11,8 @@ For details, take a look at the following workflow configuration files:
 
 ## Coding Standards
 
+We are using [`ergebnis/composer-normalize`](https://github.com/ergebnis/composer-normalize) to normalize `composer.json`.
+
 We are using [`yamllint`](https://github.com/adrienverge/yamllint) to enforce coding standards in YAML files.
 
 If you do not have `yamllint` installed yet, run
@@ -21,13 +23,27 @@ $ brew install yamllint
 
 to install `yamllint`.
 
+We are using [`friendsofphp/php-cs-fixer`](https://github.com/FriendsOfPHP/PHP-CS-Fixer) to enforce coding standards in PHP files.
+
 Run
 
 ```sh
 $ make coding-standards
 ```
 
-to detect coding standard violations.
+to automatically fix coding standard violations.
+
+## Static Code Analysis
+
+We are using [`vimeo/psalm`](https://github.com/vimeo/psalm) to statically analyze the code.
+
+Run
+
+```sh
+$ make static-code-analysis
+```
+
+to run a static code analysis.
 
 ## Tests
 
@@ -49,7 +65,7 @@ Run
 $ make
 ```
 
-to detect coding standard violations and run tests!
+to enforce coding standards, run a static code analysis, and run tests!
 
 ## Help
 
diff --git a/.github/FUNDING.yml b/.github/FUNDING.yml
index e47cb040..9fd01781 100644
--- a/.github/FUNDING.yml
+++ b/.github/FUNDING.yml
@@ -1 +1 @@
-patreon: "s_bergmann"
+github: "sebastianbergmann"
diff --git a/.github/settings.yml b/.github/settings.yml
index c2c77ef0..fe17f8e9 100644
--- a/.github/settings.yml
+++ b/.github/settings.yml
@@ -14,10 +14,18 @@ branches:
         required_approving_review_count: 1
       required_status_checks:
         contexts:
-          - "Coding Standards"
+          - "Code Coverage (7.4, highest)"
+          - "Coding Standards (7.1)"
           - "Tests (7.1, highest)"
+          - "Tests (7.1, lowest)"
           - "Tests (7.2, highest)"
+          - "Tests (7.2, lowest)"
           - "Tests (7.3, highest)"
+          - "Tests (7.3, lowest)"
+          - "Tests (7.4, highest)"
+          - "Tests (7.4, lowest)"
+          - "Tests (8.0, highest)"
+          - "Tests (8.0, lowest)"
         strict: false
       restrictions: null
 
diff --git a/.github/workflows/integrate.yaml b/.github/workflows/integrate.yaml
index 5b7e0c1d..266309ff 100644
--- a/.github/workflows/integrate.yaml
+++ b/.github/workflows/integrate.yaml
@@ -14,6 +14,11 @@ jobs:
 
     runs-on: "ubuntu-latest"
 
+    strategy:
+      matrix:
+        php-version:
+          - "7.1"
+
     steps:
       - name: "Checkout"
         uses: "actions/checkout@v2.3.1"
@@ -25,6 +30,115 @@ jobs:
           file_or_dir: "."
           strict: true
 
+      - name: "Install PHP with extensions"
+        uses: "shivammathur/setup-php@v2"
+        with:
+          coverage: "none"
+          extensions: "${{ env.PHP_EXTENSIONS }}"
+          php-version: "${{ matrix.php-version }}"
+
+      - name: "Validate composer.json and composer.lock"
+        run: "composer validate --strict"
+
+      - name: "Run ergebnis/composer-normalize"
+        run: "tools/composer-normalize --dry-run"
+
+      - name: "Create cache directory for friendsofphp/php-cs-fixer"
+        run: "mkdir -p .build/php-cs-fixer"
+
+      - name: "Cache cache directory for friendsofphp/php-cs-fixer"
+        uses: "actions/cache@v2"
+        with:
+          path: ".build/php-cs-fixer"
+          key: "php-${{ matrix.php-version }}-php-cs-fixer-${{ hashFiles('tools/php-cs-fixer') }}"
+          restore-keys: "php-${{ matrix.php-version }}-php-cs-fixer-"
+
+      - name: "Run friendsofphp/php-cs-fixer"
+        run: "tools/php-cs-fixer fix --config=.php_cs --diff --diff-format=udiff --dry-run --verbose"
+
+  static-code-analysis:
+    name: "Static Code Analysis"
+
+    runs-on: "ubuntu-latest"
+
+    strategy:
+      matrix:
+        php-version:
+          - "7.4"
+
+        dependencies:
+          - "highest"
+
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v2.3.1"
+
+      - name: "Install PHP with extensions"
+        uses: "shivammathur/setup-php@v2"
+        with:
+          coverage: "none"
+          php-version: "${{ matrix.php-version }}"
+
+      - name: "Determine composer cache directory"
+        id: "determine-composer-cache-directory"
+        run: "echo \"::set-output name=directory::$(composer config cache-dir)\""
+
+      - name: "Cache dependencies installed with composer"
+        uses: "actions/cache@v2"
+        with:
+          path: "${{ steps.determine-composer-cache-directory.outputs.directory }}"
+          key: "php-${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-${{ hashFiles('composer.lock') }}"
+          restore-keys: "php-${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-"
+
+      - name: "Install lowest dependencies from composer.json"
+        if: "matrix.dependencies == 'lowest'"
+        run: "composer update --no-interaction --no-progress --no-suggest --prefer-lowest"
+
+      - name: "Install locked dependencies from composer.lock"
+        if: "matrix.dependencies == 'locked'"
+        run: "composer install --no-interaction --no-progress --no-suggest"
+
+      - name: "Install highest dependencies from composer.json"
+        if: "matrix.dependencies == 'highest'"
+        run: "composer update --no-interaction --no-progress --no-suggest"
+
+      - name: "Create cache directory for vimeo/psalm"
+        run: "mkdir -p .build/psalm"
+
+      - name: "Cache cache directory for vimeo/psalm"
+        uses: "actions/cache@v2"
+        with:
+          path: ".build/psalm"
+          key: "php-${{ matrix.php-version }}-psalm-${{ github.sha }}"
+          restore-keys: "php-${{ matrix.php-version }}-psalm-"
+
+      - name: "Run vimeo/psalm"
+        run: "tools/psalm --config=psalm.xml --diff --diff-methods --shepherd --show-info=false --stats --threads=4"
+
+  backward-compatibility:
+    name: "Backward Compatibility"
+
+    runs-on: "ubuntu-latest"
+
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v2.3.1"
+        with:
+          fetch-depth: 0
+
+      - name: "Fetch tags"
+        run: "git fetch --depth=1 origin +refs/tags/*:refs/tags/*"
+
+      - name: "Install PHP with extensions"
+        uses: "shivammathur/setup-php@v2"
+        with:
+          php-version: "7.4"
+          coverage: "none"
+          extensions: "intl"
+
+      - name: "Run roave/backward-compatibility-check"
+        run: "tools/roave-backward-compatibility-check --from=1.0.0"
+
   tests:
     name: "Tests"
 
@@ -36,8 +150,11 @@ jobs:
           - "7.1"
           - "7.2"
           - "7.3"
+          - "7.4"
+          - "8.0"
 
         dependencies:
+          - "lowest"
           - "highest"
 
     steps:
@@ -76,12 +193,73 @@ jobs:
       - name: "Run tests with phpunit/phpunit"
         run: "vendor/bin/phpunit --configuration=phpunit.xml"
 
+  code-coverage:
+    name: "Code Coverage"
+
+    runs-on: "ubuntu-latest"
+
+    strategy:
+      matrix:
+        php-version:
+          - "7.4"
+
+        dependencies:
+          - "highest"
+
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v2.3.1"
+
+      - name: "Install PHP with extensions"
+        uses: "shivammathur/setup-php@v2"
+        with:
+          coverage: "xdebug"
+          php-version: "${{ matrix.php-version }}"
+
+      - name: "Determine composer cache directory"
+        id: "determine-composer-cache-directory"
+        run: "echo \"::set-output name=directory::$(composer config cache-dir)\""
+
+      - name: "Cache dependencies installed with composer"
+        uses: "actions/cache@v2"
+        with:
+          path: "${{ steps.determine-composer-cache-directory.outputs.directory }}"
+          key: "php-${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-${{ hashFiles('composer.lock') }}"
+          restore-keys: "php-${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-"
+
+      - name: "Install lowest dependencies from composer.json"
+        if: "matrix.dependencies == 'lowest'"
+        run: "composer update --no-interaction --no-progress --no-suggest --prefer-lowest"
+
+      - name: "Install locked dependencies from composer.lock"
+        if: "matrix.dependencies == 'locked'"
+        run: "composer install --no-interaction --no-progress --no-suggest"
+
+      - name: "Install highest dependencies from composer.json"
+        if: "matrix.dependencies == 'highest'"
+        run: "composer update --no-interaction --no-progress --no-suggest"
+
+      - name: "Dump Xdebug filter with phpunit/phpunit"
+        run: "vendor/bin/phpunit --configuration=test/Integration/phpunit.xml --dump-xdebug-filter=.build/phpunit/xdebug-filter.php"
+
+      - name: "Collect code coverage with Xdebug and phpunit/phpunit"
+        run: "vendor/bin/phpunit --configuration=test/Integration/phpunit.xml --coverage-clover=.build/logs/clover.xml --prepend=.build/phpunit/xdebug-filter.php"
+
+      - name: "Send code coverage report to Codecov.io"
+        env:
+          CODECOV_TOKEN: "${{ secrets.CODECOV_TOKEN }}"
+        run: "bash <(curl -s https://codecov.io/bash)"
+
   merge:
     name: "Merge"
 
     runs-on: "ubuntu-latest"
 
     needs:
+      - "backward-compatibility"
+      - "code-coverage"
+      - "coding-standards"
+      - "static-code-analysis"
       - "tests"
 
     if: >
diff --git a/.php_cs b/.php_cs
new file mode 100644
index 00000000..1abc0858
--- /dev/null
+++ b/.php_cs
@@ -0,0 +1,214 @@
+<?php declare(strict_types=1);
+$header = <<<'EOF'
+This file is part of sebastian/diff.
+
+(c) Sebastian Bergmann <sebastian@phpunit.de>
+
+For the full copyright and license information, please view the LICENSE
+file that was distributed with this source code.
+EOF;
+
+$finder = PhpCsFixer\Finder::create()
+    ->files()
+    ->in(__DIR__ . '/src')
+    ->in(__DIR__ . '/tests');
+
+return PhpCsFixer\Config::create()
+    ->setCacheFile(__DIR__ . '/.build/php-cs-fixer/.php_cs.cache')
+    ->setFinder($finder)
+    ->setRiskyAllowed(true)
+    ->setRules([
+        'align_multiline_comment' => true,
+        'array_indentation' => true,
+        'array_syntax' => ['syntax' => 'short'],
+        'binary_operator_spaces' => [
+            'operators' => [
+                '=' => 'align',
+                '=>' => 'align',
+            ],
+        ],
+        'blank_line_after_namespace' => true,
+        'blank_line_before_statement' => [
+            'statements' => [
+                'break',
+                'continue',
+                'declare',
+                'do',
+                'for',
+                'foreach',
+                'if',
+                'include',
+                'include_once',
+                'require',
+                'require_once',
+                'return',
+                'switch',
+                'throw',
+                'try',
+                'while',
+                'yield',
+            ],
+        ],
+        'braces' => true,
+        'cast_spaces' => true,
+        'class_attributes_separation' => ['elements' => ['const', 'method', 'property']],
+        'combine_consecutive_issets' => true,
+        'combine_consecutive_unsets' => true,
+        'compact_nullable_typehint' => true,
+        'concat_space' => ['spacing' => 'one'],
+        'declare_equal_normalize' => ['space' => 'none'],
+        'declare_strict_types' => true,
+        'dir_constant' => true,
+        'elseif' => true,
+        'encoding' => true,
+        'full_opening_tag' => true,
+        'function_declaration' => true,
+        'global_namespace_import' => [
+            'import_classes' => true,
+            'import_constants' => true,
+            'import_functions' => true,
+        ],
+        'header_comment' => ['header' => $header, 'separate' => 'none'],
+        'indentation_type' => true,
+        'is_null' => true,
+        'line_ending' => true,
+        'list_syntax' => ['syntax' => 'short'],
+        'logical_operators' => true,
+        'lowercase_cast' => true,
+        'lowercase_constants' => true,
+        'lowercase_keywords' => true,
+        'lowercase_static_reference' => true,
+        'magic_constant_casing' => true,
+        'method_argument_space' => ['ensure_fully_multiline' => true],
+        'modernize_types_casting' => true,
+        'multiline_comment_opening_closing' => true,
+        'multiline_whitespace_before_semicolons' => true,
+        'native_constant_invocation' => false,
+        'native_function_casing' => false,
+        'native_function_invocation' => false,
+        'new_with_braces' => false,
+        'no_alias_functions' => true,
+        'no_alternative_syntax' => true,
+        'no_blank_lines_after_class_opening' => true,
+        'no_blank_lines_after_phpdoc' => true,
+        'no_blank_lines_before_namespace' => true,
+        'no_closing_tag' => true,
+        'no_empty_comment' => true,
+        'no_empty_phpdoc' => true,
+        'no_empty_statement' => true,
+        'no_extra_blank_lines' => true,
+        'no_homoglyph_names' => true,
+        'no_leading_import_slash' => true,
+        'no_leading_namespace_whitespace' => true,
+        'no_mixed_echo_print' => ['use' => 'print'],
+        'no_multiline_whitespace_around_double_arrow' => true,
+        'no_null_property_initialization' => true,
+        'no_php4_constructor' => true,
+        'no_short_bool_cast' => true,
+        'no_short_echo_tag' => true,
+        'no_singleline_whitespace_before_semicolons' => true,
+        'no_spaces_after_function_name' => true,
+        'no_spaces_inside_parenthesis' => true,
+        'no_superfluous_elseif' => true,
+        'no_superfluous_phpdoc_tags' => [
+            'allow_mixed' => true,
+        ],
+        'no_trailing_comma_in_list_call' => true,
+        'no_trailing_comma_in_singleline_array' => true,
+        'no_trailing_whitespace' => true,
+        'no_trailing_whitespace_in_comment' => true,
+        'no_unneeded_control_parentheses' => true,
+        'no_unneeded_curly_braces' => true,
+        'no_unneeded_final_method' => true,
+        'no_unreachable_default_argument_value' => true,
+        'no_unset_on_property' => true,
+        'no_unused_imports' => true,
+        'no_useless_else' => true,
+        'no_useless_return' => true,
+        'no_whitespace_before_comma_in_array' => true,
+        'no_whitespace_in_blank_line' => true,
+        'non_printable_character' => true,
+        'normalize_index_brace' => true,
+        'object_operator_without_whitespace' => true,
+        'ordered_class_elements' => [
+            'order' => [
+                'use_trait',
+                'constant_public',
+                'constant_protected',
+                'constant_private',
+                'property_public_static',
+                'property_protected_static',
+                'property_private_static',
+                'property_public',
+                'property_protected',
+                'property_private',
+                'method_public_static',
+                'construct',
+                'destruct',
+                'magic',
+                'phpunit',
+                'method_public',
+                'method_protected',
+                'method_private',
+                'method_protected_static',
+                'method_private_static',
+            ],
+        ],
+        'ordered_imports' => [
+            'imports_order' => [
+                PhpCsFixer\Fixer\Import\OrderedImportsFixer::IMPORT_TYPE_CONST,
+                PhpCsFixer\Fixer\Import\OrderedImportsFixer::IMPORT_TYPE_FUNCTION,
+                PhpCsFixer\Fixer\Import\OrderedImportsFixer::IMPORT_TYPE_CLASS,
+            ]
+        ],
+        'ordered_interfaces' => [
+            'direction' => 'ascend',
+            'order' => 'alpha',
+        ],
+        'phpdoc_add_missing_param_annotation' => false,
+        'phpdoc_align' => true,
+        'phpdoc_annotation_without_dot' => true,
+        'phpdoc_indent' => true,
+        'phpdoc_no_access' => true,
+        'phpdoc_no_empty_return' => true,
+        'phpdoc_no_package' => true,
+        'phpdoc_order' => true,
+        'phpdoc_return_self_reference' => true,
+        'phpdoc_scalar' => true,
+        'phpdoc_separation' => true,
+        'phpdoc_single_line_var_spacing' => true,
+        'phpdoc_summary' => true,
+        'phpdoc_to_comment' => true,
+        'phpdoc_trim' => true,
+        'phpdoc_trim_consecutive_blank_line_separation' => true,
+        'phpdoc_types' => ['groups' => ['simple', 'meta']],
+        'phpdoc_types_order' => true,
+        'phpdoc_var_without_name' => true,
+        'pow_to_exponentiation' => true,
+        'protected_to_private' => true,
+        'return_assignment' => true,
+        'return_type_declaration' => ['space_before' => 'none'],
+        'self_accessor' => true,
+        'semicolon_after_instruction' => true,
+        'set_type_to_cast' => true,
+        'short_scalar_cast' => true,
+        'simplified_null_return' => false,
+        'single_blank_line_at_eof' => true,
+        'single_import_per_statement' => true,
+        'single_line_after_imports' => true,
+        'single_quote' => true,
+        'standardize_not_equals' => true,
+        'ternary_to_null_coalescing' => true,
+        'trailing_comma_in_multiline_array' => true,
+        'trim_array_spaces' => true,
+        'unary_operator_spaces' => true,
+        'visibility_required' => [
+            'elements' => [
+                'const',
+                'method',
+                'property',
+            ],
+        ],
+        'void_return' => true,
+        'whitespace_after_comma_in_array' => true,
+    ]);
diff --git a/.php_cs.dist b/.php_cs.dist
deleted file mode 100644
index 92146075..00000000
--- a/.php_cs.dist
+++ /dev/null
@@ -1,168 +0,0 @@
-<?php declare(strict_types=1);
-$header = <<<'EOF'
-This file is part of sebastian/diff.
-
-(c) Sebastian Bergmann <sebastian@phpunit.de>
-
-For the full copyright and license information, please view the LICENSE
-file that was distributed with this source code.
-EOF;
-
-return PhpCsFixer\Config::create()
-    ->setRiskyAllowed(true)
-    ->setRules(
-        [
-            'array_syntax' => ['syntax' => 'short'],
-            'binary_operator_spaces' => [
-                'operators' => [
-                    '=' => 'align',
-                    '=>' => 'align',
-                ],
-            ],
-            'blank_line_after_namespace' => true,
-            'blank_line_before_statement' => [
-                'statements' => [
-                    'break',
-                    'continue',
-                    'declare',
-                    'do',
-                    'for',
-                    'foreach',
-                    'if',
-                    'include',
-                    'include_once',
-                    'require',
-                    'require_once',
-                    'return',
-                    'switch',
-                    'throw',
-                    'try',
-                    'while',
-                    'yield',
-                ],
-            ],
-            'braces' => true,
-            'cast_spaces' => true,
-            'class_attributes_separation' => ['elements' => ['method']],
-            'compact_nullable_typehint' => true,
-            'concat_space' => ['spacing' => 'one'],
-            'declare_equal_normalize' => ['space' => 'none'],
-            'declare_strict_types' => true,
-            'dir_constant' => true,
-            'elseif' => true,
-            'encoding' => true,
-            'full_opening_tag' => true,
-            'function_declaration' => true,
-            'header_comment' => ['header' => $header, 'separate' => 'none'],
-            'indentation_type' => true,
-            'line_ending' => true,
-            'list_syntax' => ['syntax' => 'short'],
-            'lowercase_cast' => true,
-            'lowercase_constants' => true,
-            'lowercase_keywords' => true,
-            'magic_constant_casing' => true,
-            'method_argument_space' => ['ensure_fully_multiline' => true],
-            'modernize_types_casting' => true,
-            'native_function_casing' => true,
-            'native_function_invocation' => true,
-            'no_alias_functions' => true,
-            'no_blank_lines_after_class_opening' => true,
-            'no_blank_lines_after_phpdoc' => true,
-            'no_closing_tag' => true,
-            'no_empty_comment' => true,
-            'no_empty_phpdoc' => true,
-            'no_empty_statement' => true,
-            'no_extra_blank_lines' => true,
-            'no_homoglyph_names' => true,
-            'no_leading_import_slash' => true,
-            'no_leading_namespace_whitespace' => true,
-            'no_mixed_echo_print' => ['use' => 'print'],
-            'no_null_property_initialization' => true,
-            'no_short_bool_cast' => true,
-            'no_short_echo_tag' => true,
-            'no_singleline_whitespace_before_semicolons' => true,
-            'no_spaces_after_function_name' => true,
-            'no_spaces_inside_parenthesis' => true,
-            'no_superfluous_elseif' => true,
-            'no_trailing_comma_in_list_call' => true,
-            'no_trailing_comma_in_singleline_array' => true,
-            'no_trailing_whitespace' => true,
-            'no_trailing_whitespace_in_comment' => true,
-            'no_unneeded_control_parentheses' => true,
-            'no_unneeded_curly_braces' => true,
-            'no_unneeded_final_method' => true,
-            'no_unreachable_default_argument_value' => true,
-            'no_unused_imports' => true,
-            'no_useless_else' => true,
-            'no_whitespace_before_comma_in_array' => true,
-            'no_whitespace_in_blank_line' => true,
-            'non_printable_character' => true,
-            'normalize_index_brace' => true,
-            'object_operator_without_whitespace' => true,
-            'ordered_class_elements' => [
-                'order' => [
-                    'use_trait',
-                    'constant_public',
-                    'constant_protected',
-                    'constant_private',
-                    'property_public_static',
-                    'property_protected_static',
-                    'property_private_static',
-                    'property_public',
-                    'property_protected',
-                    'property_private',
-                    'method_public_static',
-                    'construct',
-                    'destruct',
-                    'magic',
-                    'phpunit',
-                    'method_public',
-                    'method_protected',
-                    'method_private',
-                    'method_protected_static',
-                    'method_private_static',
-                ],
-            ],
-            'ordered_imports' => true,
-            'phpdoc_add_missing_param_annotation' => true,
-            'phpdoc_align' => true,
-            'phpdoc_annotation_without_dot' => true,
-            'phpdoc_indent' => true,
-            'phpdoc_no_access' => true,
-            'phpdoc_no_empty_return' => true,
-            'phpdoc_no_package' => true,
-            'phpdoc_order' => true,
-            'phpdoc_return_self_reference' => true,
-            'phpdoc_scalar' => true,
-            'phpdoc_separation' => true,
-            'phpdoc_single_line_var_spacing' => true,
-            'phpdoc_to_comment' => true,
-            'phpdoc_trim' => true,
-            'phpdoc_types' => true,
-            'phpdoc_types_order' => true,
-            'phpdoc_var_without_name' => true,
-            'pow_to_exponentiation' => true,
-            'protected_to_private' => true,
-            'return_type_declaration' => ['space_before' => 'none'],
-            'self_accessor' => true,
-            'short_scalar_cast' => true,
-            'simplified_null_return' => true,
-            'single_blank_line_at_eof' => true,
-            'single_import_per_statement' => true,
-            'single_line_after_imports' => true,
-            'single_quote' => true,
-            'standardize_not_equals' => true,
-            'ternary_to_null_coalescing' => true,
-            'trim_array_spaces' => true,
-            'unary_operator_spaces' => true,
-            'visibility_required' => true,
-            'void_return' => true,
-            'whitespace_after_comma_in_array' => true,
-        ]
-    )
-    ->setFinder(
-        PhpCsFixer\Finder::create()
-        ->files()
-        ->in(__DIR__ . '/src')
-        ->in(__DIR__ . '/tests')
-    );
diff --git a/ChangeLog.md b/ChangeLog.md
index 76ccd877..df68a730 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -2,6 +2,24 @@
 
 All notable changes are documented in this file using the [Keep a CHANGELOG](http://keepachangelog.com/) principles.
 
+## [4.0.2] - 2020-06-30
+
+### Added
+
+* This component is now supported on PHP 8
+
+## [4.0.1] - 2020-05-08
+
+### Fixed
+
+* [#99](https://github.com/sebastianbergmann/diff/pull/99): Regression in unified diff output of identical strings
+
+## [4.0.0] - 2020-02-07
+
+### Removed
+
+* Removed support for PHP 7.1 and PHP 7.2
+
 ## [3.0.2] - 2019-02-04
 
 ### Changed
@@ -28,24 +46,27 @@ All notable changes are documented in this file using the [Keep a CHANGELOG](htt
 
 ### Fixed
 
-* Fixed [#70](https://github.com/sebastianbergmann/diff/issues/70): Diffing of arrays no longer works
+* [#70](https://github.com/sebastianbergmann/diff/issues/70): Diffing of arrays no longer works
 
 ## [2.0.1] - 2017-08-03
 
 ### Fixed
 
-* Fixed [#66](https://github.com/sebastianbergmann/diff/pull/66): Restored backwards compatibility for PHPUnit 6.1.4, 6.2.0, 6.2.1, 6.2.2, and 6.2.3
+* [#66](https://github.com/sebastianbergmann/diff/pull/66): Restored backwards compatibility for PHPUnit 6.1.4, 6.2.0, 6.2.1, 6.2.2, and 6.2.3
 
 ## [2.0.0] - 2017-07-11 [YANKED]
 
 ### Added
 
-* Implemented [#64](https://github.com/sebastianbergmann/diff/pull/64): Show line numbers for chunks of a diff
+* [#64](https://github.com/sebastianbergmann/diff/pull/64): Show line numbers for chunks of a diff
 
 ### Removed
 
 * This component is no longer supported on PHP 5.6
 
+[4.0.2]: https://github.com/sebastianbergmann/diff/compare/4.0.1...4.0.2
+[4.0.1]: https://github.com/sebastianbergmann/diff/compare/4.0.0...4.0.1
+[4.0.0]: https://github.com/sebastianbergmann/diff/compare/3.0.2...4.0.0
 [3.0.2]: https://github.com/sebastianbergmann/diff/compare/3.0.1...3.0.2
 [3.0.1]: https://github.com/sebastianbergmann/diff/compare/3.0.0...3.0.1
 [3.0.0]: https://github.com/sebastianbergmann/diff/compare/2.0...3.0.0
diff --git a/LICENSE b/LICENSE
index 3ad1d7c3..f22f31cf 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 sebastian/diff
 
-Copyright (c) 2002-2019, Sebastian Bergmann <sebastian@phpunit.de>.
+Copyright (c) 2002-2020, Sebastian Bergmann <sebastian@phpunit.de>.
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
diff --git a/Makefile b/Makefile
index 2dbd71b4..7c156d39 100644
--- a/Makefile
+++ b/Makefile
@@ -1,9 +1,12 @@
 .PHONY: it
-it: coding-standards tests ## Runs the coding-standards and tests targets
+it: coding-standards static-code-analysis tests ## Runs the coding-standards, static-code-analysis, and tests targets
 
 .PHONY: coding-standards
-coding-standards: vendor ## Lints YAML files with yamllint
+coding-standards: vendor ## Normalizes composer.json with ergebnis/composer-normalize, lints YAML files with yamllint and fixes code style issues with friendsofphp/php-cs-fixer
+	tools/composer-normalize
 	yamllint -c .yamllint.yaml --strict .
+	mkdir -p .build/php-cs-fixer
+	tools/php-cs-fixer fix --config=.php_cs --diff --diff-format=udiff --verbose
 
 .PHONY: help
 help: ## Displays this list of targets with descriptions
@@ -12,8 +15,15 @@ help: ## Displays this list of targets with descriptions
 .PHONY: tests
 tests: vendor ## Runs tests with phpunit/phpunit
 	mkdir -p .build/phpunit
+	composer dump-autoload
 	vendor/bin/phpunit --configuration=phpunit.xml
 
+.PHONY: static-code-analysis
+static-code-analysis: vendor ## Runs a static code analysis with vimeo/psalm
+	mkdir -p .build/psalm
+	composer dump-autoload
+	tools/psalm --config=psalm.xml --diff --diff-methods --show-info=false --stats --threads=4
+
 vendor: composer.json
 	composer validate --strict
 	composer install --no-interaction --no-progress --no-suggest
diff --git a/README.md b/README.md
index 194292c4..67921d16 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,9 @@
 [![Prune](https://github.com/localheinz/diff/workflows/Prune/badge.svg?branch=main)](https://github.com/localheinz/diff/actions)
 [![Release](https://github.com/localheinz/diff/workflows/Release/badge.svg?branch=main)](https://github.com/localheinz/diff/actions)
 
+[![Code Coverage](https://codecov.io/gh/ergebnis/json-normalizer/branch/main/graph/badge.svg)](https://codecov.io/gh/ergebnis/json-normalizer)
+[![Type Coverage](https://shepherd.dev/github/ergebnis/json-normalizer/coverage.svg)](https://shepherd.dev/github/ergebnis/json-normalizer)
+
 [![Latest Stable Version](https://poser.pugx.org/localheinz/diff/v/stable)](https://packagist.org/packages/localheinz/diff)
 [![Total Downloads](https://poser.pugx.org/localheinz/diff/downloads)](https://packagist.org/packages/localheinz/diff)
 
diff --git a/composer.json b/composer.json
index 592e690c..ba2cc55c 100644
--- a/composer.json
+++ b/composer.json
@@ -1,8 +1,13 @@
 {
     "name": "localheinz/diff",
     "description": "Fork of sebastian/diff for use with ergebnis/composer-normalize",
-    "keywords": ["diff", "udiff", "unidiff", "unified diff"],
-    "homepage": "https://github.com/sebastianbergmann/diff",
+    "keywords": [
+        "diff",
+        "udiff",
+        "unidiff",
+        "unified diff"
+    ],
+    "homepage": "https://github.com/localheinz/diff",
     "license": "BSD-3-Clause",
     "authors": [
         {
@@ -15,11 +20,18 @@
         }
     ],
     "require": {
-        "php": "^7.1"
+        "php": "^7.1 || ^8.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^7.5 || ^8.0",
-        "symfony/process": "^2 || ^3.3 || ^4"
+        "symfony/process": "^4.2 || ^5"
+    },
+    "config": {
+        "optimize-autoloader": true,
+        "platform": {
+            "php": "7.1.33"
+        },
+        "sort-packages": true
     },
     "autoload": {
         "classmap": [
@@ -30,5 +42,6 @@
         "classmap": [
             "tests/"
         ]
-    }
+    },
+    "prefer-stable": true
 }
diff --git a/phive.xml b/phive.xml
new file mode 100644
index 00000000..563fedfb
--- /dev/null
+++ b/phive.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phive xmlns="https://phar.io/phive">
+  <phar name="composer-normalize" version="^2.5.1" installed="2.5.1" location="./tools/composer-normalize" copy="true"/>
+  <phar name="php-cs-fixer" version="^2.16.4" installed="2.16.4" location="./tools/php-cs-fixer" copy="true"/>
+  <phar name="psalm" version="^3.12.2" installed="3.12.2" location="./tools/psalm" copy="true"/>
+  <phar name="roave/backwardcompatibilitycheck" version="^5.0.0" installed="5.0.0" location="./tools/roave-backward-compatibility-check" copy="true"/>
+</phive>
diff --git a/psalm.xml b/psalm.xml
new file mode 100644
index 00000000..047573a3
--- /dev/null
+++ b/psalm.xml
@@ -0,0 +1,55 @@
+<?xml version="1.0"?>
+<psalm
+    totallyTyped="false"
+    cacheDirectory=".build/psalm"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="src" />
+        <ignoreFiles>
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+
+    <issueHandlers>
+        <LessSpecificReturnType errorLevel="info" />
+
+        <!-- level 3 issues - slightly lazy code writing, but provably low false-negatives -->
+
+        <DeprecatedMethod errorLevel="info" />
+        <DeprecatedProperty errorLevel="info" />
+        <DeprecatedClass errorLevel="info" />
+        <DeprecatedConstant errorLevel="info" />
+        <DeprecatedFunction errorLevel="info" />
+        <DeprecatedInterface errorLevel="info" />
+        <DeprecatedTrait errorLevel="info" />
+
+        <InternalMethod errorLevel="info" />
+        <InternalProperty errorLevel="info" />
+        <InternalClass errorLevel="info" />
+
+        <MissingClosureReturnType errorLevel="info" />
+        <MissingReturnType errorLevel="info" />
+        <MissingPropertyType errorLevel="info" />
+        <InvalidDocblock errorLevel="info" />
+        <MisplacedRequiredParam errorLevel="info" />
+
+        <PropertyNotSetInConstructor errorLevel="info" />
+        <MissingConstructor errorLevel="info" />
+        <MissingClosureParamType errorLevel="info" />
+        <MissingParamType errorLevel="info" />
+
+        <RedundantCondition errorLevel="info" />
+
+        <DocblockTypeContradiction errorLevel="info" />
+        <RedundantConditionGivenDocblockType errorLevel="info" />
+
+        <UnresolvableInclude errorLevel="info" />
+
+        <RawObjectIteration errorLevel="info" />
+
+        <InvalidStringClass errorLevel="info" />
+    </issueHandlers>
+</psalm>
diff --git a/src/Chunk.php b/src/Chunk.php
index 64e2c486..8cce2cd9 100644
--- a/src/Chunk.php
+++ b/src/Chunk.php
@@ -7,7 +7,6 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 final class Chunk
diff --git a/src/Diff.php b/src/Diff.php
index 0917574f..0eafa059 100644
--- a/src/Diff.php
+++ b/src/Diff.php
@@ -7,7 +7,6 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 final class Diff
@@ -28,8 +27,6 @@ final class Diff
     private $chunks;
 
     /**
-     * @param string  $from
-     * @param string  $to
      * @param Chunk[] $chunks
      */
     public function __construct(string $from, string $to, array $chunks = [])
diff --git a/src/Differ.php b/src/Differ.php
index 18c42f12..583d2da7 100644
--- a/src/Differ.php
+++ b/src/Differ.php
@@ -7,21 +7,42 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
+use const PHP_INT_SIZE;
+use const PREG_SPLIT_DELIM_CAPTURE;
+use const PREG_SPLIT_NO_EMPTY;
+use function array_shift;
+use function array_unshift;
+use function array_values;
+use function count;
+use function current;
+use function end;
+use function get_class;
+use function gettype;
+use function is_array;
+use function is_object;
+use function is_string;
+use function key;
+use function min;
+use function preg_split;
+use function prev;
+use function reset;
+use function sprintf;
+use function substr;
 use Localheinz\Diff\Output\DiffOutputBuilderInterface;
 use Localheinz\Diff\Output\UnifiedDiffOutputBuilder;
 
-/**
- * Diff implementation.
- */
 final class Differ
 {
     public const OLD                     = 0;
+
     public const ADDED                   = 1;
+
     public const REMOVED                 = 2;
+
     public const DIFF_LINE_END_WARNING   = 3;
+
     public const NO_LINE_END_EOF_WARNING = 4;
 
     /**
@@ -40,16 +61,16 @@ public function __construct($outputBuilder = null)
             $this->outputBuilder = $outputBuilder;
         } elseif (null === $outputBuilder) {
             $this->outputBuilder = new UnifiedDiffOutputBuilder;
-        } elseif (\is_string($outputBuilder)) {
+        } elseif (is_string($outputBuilder)) {
             // PHPUnit 6.1.4, 6.2.0, 6.2.1, 6.2.2, and 6.2.3 support
             // @see https://github.com/sebastianbergmann/phpunit/issues/2734#issuecomment-314514056
             // @deprecated
             $this->outputBuilder = new UnifiedDiffOutputBuilder($outputBuilder);
         } else {
             throw new InvalidArgumentException(
-                \sprintf(
+                sprintf(
                     'Expected builder to be an instance of DiffOutputBuilderInterface, <null> or a string, got %s.',
-                    \is_object($outputBuilder) ? 'instance of "' . \get_class($outputBuilder) . '"' : \gettype($outputBuilder) . ' "' . $outputBuilder . '"'
+                    is_object($outputBuilder) ? 'instance of "' . get_class($outputBuilder) . '"' : gettype($outputBuilder) . ' "' . $outputBuilder . '"'
                 )
             );
         }
@@ -58,11 +79,8 @@ public function __construct($outputBuilder = null)
     /**
      * Returns the diff between two arrays or strings as string.
      *
-     * @param array|string                            $from
-     * @param array|string                            $to
-     * @param null|LongestCommonSubsequenceCalculator $lcs
-     *
-     * @return string
+     * @param array|string $from
+     * @param array|string $to
      */
     public function diff($from, $to, LongestCommonSubsequenceCalculator $lcs = null): string
     {
@@ -89,20 +107,18 @@ public function diff($from, $to, LongestCommonSubsequenceCalculator $lcs = null)
      * @param array|string                       $from
      * @param array|string                       $to
      * @param LongestCommonSubsequenceCalculator $lcs
-     *
-     * @return array
      */
     public function diffToArray($from, $to, LongestCommonSubsequenceCalculator $lcs = null): array
     {
-        if (\is_string($from)) {
+        if (is_string($from)) {
             $from = $this->splitStringByLines($from);
-        } elseif (!\is_array($from)) {
+        } elseif (!is_array($from)) {
             throw new InvalidArgumentException('"from" must be an array or string.');
         }
 
-        if (\is_string($to)) {
+        if (is_string($to)) {
             $to = $this->splitStringByLines($to);
-        } elseif (!\is_array($to)) {
+        } elseif (!is_array($to)) {
             throw new InvalidArgumentException('"to" must be an array or string.');
         }
 
@@ -112,36 +128,36 @@ public function diffToArray($from, $to, LongestCommonSubsequenceCalculator $lcs
             $lcs = $this->selectLcsImplementation($from, $to);
         }
 
-        $common = $lcs->calculate(\array_values($from), \array_values($to));
+        $common = $lcs->calculate(array_values($from), array_values($to));
         $diff   = [];
 
         foreach ($start as $token) {
             $diff[] = [$token, self::OLD];
         }
 
-        \reset($from);
-        \reset($to);
+        reset($from);
+        reset($to);
 
         foreach ($common as $token) {
-            while (($fromToken = \reset($from)) !== $token) {
-                $diff[] = [\array_shift($from), self::REMOVED];
+            while (($fromToken = reset($from)) !== $token) {
+                $diff[] = [array_shift($from), self::REMOVED];
             }
 
-            while (($toToken = \reset($to)) !== $token) {
-                $diff[] = [\array_shift($to), self::ADDED];
+            while (($toToken = reset($to)) !== $token) {
+                $diff[] = [array_shift($to), self::ADDED];
             }
 
             $diff[] = [$token, self::OLD];
 
-            \array_shift($from);
-            \array_shift($to);
+            array_shift($from);
+            array_shift($to);
         }
 
-        while (($token = \array_shift($from)) !== null) {
+        while (($token = array_shift($from)) !== null) {
             $diff[] = [$token, self::REMOVED];
         }
 
-        while (($token = \array_shift($to)) !== null) {
+        while (($token = array_shift($to)) !== null) {
             $diff[] = [$token, self::ADDED];
         }
 
@@ -150,7 +166,7 @@ public function diffToArray($from, $to, LongestCommonSubsequenceCalculator $lcs
         }
 
         if ($this->detectUnmatchedLineEndings($diff)) {
-            \array_unshift($diff, ["#Warning: Strings contain different line endings!\n", self::DIFF_LINE_END_WARNING]);
+            array_unshift($diff, ["#Warning: Strings contain different line endings!\n", self::DIFF_LINE_END_WARNING]);
         }
 
         return $diff;
@@ -159,13 +175,11 @@ public function diffToArray($from, $to, LongestCommonSubsequenceCalculator $lcs
     /**
      * Casts variable to string if it is not a string or array.
      *
-     * @param mixed $input
-     *
      * @return array|string
      */
     private function normalizeDiffInput($input)
     {
-        if (!\is_array($input) && !\is_string($input)) {
+        if (!is_array($input) && !is_string($input)) {
             return (string) $input;
         }
 
@@ -174,22 +188,12 @@ private function normalizeDiffInput($input)
 
     /**
      * Checks if input is string, if so it will split it line-by-line.
-     *
-     * @param string $input
-     *
-     * @return array
      */
     private function splitStringByLines(string $input): array
     {
-        return \preg_split('/(.*\R)/', $input, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
+        return preg_split('/(.*\R)/', $input, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
     }
 
-    /**
-     * @param array $from
-     * @param array $to
-     *
-     * @return LongestCommonSubsequenceCalculator
-     */
     private function selectLcsImplementation(array $from, array $to): LongestCommonSubsequenceCalculator
     {
         // We do not want to use the time-efficient implementation if its memory
@@ -208,24 +212,17 @@ private function selectLcsImplementation(array $from, array $to): LongestCommonS
     /**
      * Calculates the estimated memory footprint for the DP-based method.
      *
-     * @param array $from
-     * @param array $to
-     *
      * @return float|int
      */
     private function calculateEstimatedFootprint(array $from, array $to)
     {
         $itemSize = PHP_INT_SIZE === 4 ? 76 : 144;
 
-        return $itemSize * \min(\count($from), \count($to)) ** 2;
+        return $itemSize * min(count($from), count($to)) ** 2;
     }
 
     /**
      * Returns true if line ends don't match in a diff.
-     *
-     * @param array $diff
-     *
-     * @return bool
      */
     private function detectUnmatchedLineEndings(array $diff): bool
     {
@@ -267,11 +264,11 @@ private function detectUnmatchedLineEndings(array $diff): bool
 
     private function getLinebreak($line): string
     {
-        if (!\is_string($line)) {
+        if (!is_string($line)) {
             return '';
         }
 
-        $lc = \substr($line, -1);
+        $lc = substr($line, -1);
 
         if ("\r" === $lc) {
             return "\r";
@@ -281,7 +278,7 @@ private function getLinebreak($line): string
             return '';
         }
 
-        if ("\r\n" === \substr($line, -2)) {
+        if ("\r\n" === substr($line, -2)) {
             return "\r\n";
         }
 
@@ -293,10 +290,10 @@ private static function getArrayDiffParted(array &$from, array &$to): array
         $start = [];
         $end   = [];
 
-        \reset($to);
+        reset($to);
 
         foreach ($from as $k => $v) {
-            $toK = \key($to);
+            $toK = key($to);
 
             if ($toK === $k && $v === $to[$k]) {
                 $start[$k] = $v;
@@ -307,19 +304,19 @@ private static function getArrayDiffParted(array &$from, array &$to): array
             }
         }
 
-        \end($from);
-        \end($to);
+        end($from);
+        end($to);
 
         do {
-            $fromK = \key($from);
-            $toK   = \key($to);
+            $fromK = key($from);
+            $toK   = key($to);
 
-            if (null === $fromK || null === $toK || \current($from) !== \current($to)) {
+            if (null === $fromK || null === $toK || current($from) !== current($to)) {
                 break;
             }
 
-            \prev($from);
-            \prev($to);
+            prev($from);
+            prev($to);
 
             $end = [$fromK => $from[$fromK]] + $end;
             unset($from[$fromK], $to[$toK]);
diff --git a/src/Exception/ConfigurationException.php b/src/Exception/ConfigurationException.php
index 9497b941..ce7cacba 100644
--- a/src/Exception/ConfigurationException.php
+++ b/src/Exception/ConfigurationException.php
@@ -7,31 +7,29 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
+use function get_class;
+use function gettype;
+use function is_object;
+use function sprintf;
+use Exception;
+
 final class ConfigurationException extends InvalidArgumentException
 {
-    /**
-     * @param string          $option
-     * @param string          $expected
-     * @param mixed           $value
-     * @param int             $code
-     * @param null|\Exception $previous
-     */
     public function __construct(
         string $option,
         string $expected,
         $value,
         int $code = 0,
-        \Exception $previous = null
+        Exception $previous = null
     ) {
         parent::__construct(
-            \sprintf(
+            sprintf(
                 'Option "%s" must be %s, got "%s".',
                 $option,
                 $expected,
-                \is_object($value) ? \get_class($value) : (null === $value ? '<null>' : \gettype($value) . '#' . $value)
+                is_object($value) ? get_class($value) : (null === $value ? '<null>' : gettype($value) . '#' . $value)
             ),
             $code,
             $previous
diff --git a/src/Exception/Exception.php b/src/Exception/Exception.php
index 51ea1c9c..3f1c9ae7 100644
--- a/src/Exception/Exception.php
+++ b/src/Exception/Exception.php
@@ -7,7 +7,6 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 interface Exception
diff --git a/src/Exception/InvalidArgumentException.php b/src/Exception/InvalidArgumentException.php
index 90aa81b5..9cc78205 100644
--- a/src/Exception/InvalidArgumentException.php
+++ b/src/Exception/InvalidArgumentException.php
@@ -7,7 +7,6 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 class InvalidArgumentException extends \InvalidArgumentException implements Exception
diff --git a/src/Line.php b/src/Line.php
index 1918a476..66b12639 100644
--- a/src/Line.php
+++ b/src/Line.php
@@ -7,13 +7,14 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 final class Line
 {
     public const ADDED     = 1;
+
     public const REMOVED   = 2;
+
     public const UNCHANGED = 3;
 
     /**
diff --git a/src/LongestCommonSubsequenceCalculator.php b/src/LongestCommonSubsequenceCalculator.php
index f9732bc9..85bf7041 100644
--- a/src/LongestCommonSubsequenceCalculator.php
+++ b/src/LongestCommonSubsequenceCalculator.php
@@ -7,18 +7,12 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 interface LongestCommonSubsequenceCalculator
 {
     /**
      * Calculates the longest common subsequence of two arrays.
-     *
-     * @param array $from
-     * @param array $to
-     *
-     * @return array
      */
     public function calculate(array $from, array $to): array;
 }
diff --git a/src/MemoryEfficientLongestCommonSubsequenceCalculator.php b/src/MemoryEfficientLongestCommonSubsequenceCalculator.php
index 30b1fcfc..673815f2 100644
--- a/src/MemoryEfficientLongestCommonSubsequenceCalculator.php
+++ b/src/MemoryEfficientLongestCommonSubsequenceCalculator.php
@@ -7,9 +7,16 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
+use function array_fill;
+use function array_merge;
+use function array_reverse;
+use function array_slice;
+use function count;
+use function in_array;
+use function max;
+
 final class MemoryEfficientLongestCommonSubsequenceCalculator implements LongestCommonSubsequenceCalculator
 {
     /**
@@ -17,15 +24,15 @@ final class MemoryEfficientLongestCommonSubsequenceCalculator implements Longest
      */
     public function calculate(array $from, array $to): array
     {
-        $cFrom = \count($from);
-        $cTo   = \count($to);
+        $cFrom = count($from);
+        $cTo   = count($to);
 
         if ($cFrom === 0) {
             return [];
         }
 
         if ($cFrom === 1) {
-            if (\in_array($from[0], $to, true)) {
+            if (in_array($from[0], $to, true)) {
                 return [$from[0]];
             }
 
@@ -33,10 +40,10 @@ public function calculate(array $from, array $to): array
         }
 
         $i         = (int) ($cFrom / 2);
-        $fromStart = \array_slice($from, 0, $i);
-        $fromEnd   = \array_slice($from, $i);
+        $fromStart = array_slice($from, 0, $i);
+        $fromEnd   = array_slice($from, $i);
         $llB       = $this->length($fromStart, $to);
-        $llE       = $this->length(\array_reverse($fromEnd), \array_reverse($to));
+        $llE       = $this->length(array_reverse($fromEnd), array_reverse($to));
         $jMax      = 0;
         $max       = 0;
 
@@ -49,10 +56,10 @@ public function calculate(array $from, array $to): array
             }
         }
 
-        $toStart = \array_slice($to, 0, $jMax);
-        $toEnd   = \array_slice($to, $jMax);
+        $toStart = array_slice($to, 0, $jMax);
+        $toEnd   = array_slice($to, $jMax);
 
-        return \array_merge(
+        return array_merge(
             $this->calculate($fromStart, $toStart),
             $this->calculate($fromEnd, $toEnd)
         );
@@ -60,9 +67,9 @@ public function calculate(array $from, array $to): array
 
     private function length(array $from, array $to): array
     {
-        $current = \array_fill(0, \count($to) + 1, 0);
-        $cFrom   = \count($from);
-        $cTo     = \count($to);
+        $current = array_fill(0, count($to) + 1, 0);
+        $cFrom   = count($from);
+        $cTo     = count($to);
 
         for ($i = 0; $i < $cFrom; $i++) {
             $prev = $current;
@@ -71,7 +78,7 @@ private function length(array $from, array $to): array
                 if ($from[$i] === $to[$j]) {
                     $current[$j + 1] = $prev[$j] + 1;
                 } else {
-                    $current[$j + 1] = \max($current[$j], $prev[$j + 1]);
+                    $current[$j + 1] = max($current[$j], $prev[$j + 1]);
                 }
             }
         }
diff --git a/src/Output/AbstractChunkOutputBuilder.php b/src/Output/AbstractChunkOutputBuilder.php
index 7b9188ed..1ca27e27 100644
--- a/src/Output/AbstractChunkOutputBuilder.php
+++ b/src/Output/AbstractChunkOutputBuilder.php
@@ -7,23 +7,19 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
+use function count;
+
 abstract class AbstractChunkOutputBuilder implements DiffOutputBuilderInterface
 {
     /**
      * Takes input of the diff array and returns the common parts.
      * Iterates through diff line by line.
-     *
-     * @param array $diff
-     * @param int   $lineThreshold
-     *
-     * @return array
      */
     protected function getCommonChunks(array $diff, int $lineThreshold = 5): array
     {
-        $diffSize     = \count($diff);
+        $diffSize     = count($diff);
         $capturing    = false;
         $chunkStart   = 0;
         $chunkSize    = 0;
diff --git a/src/Output/DiffOnlyOutputBuilder.php b/src/Output/DiffOnlyOutputBuilder.php
index cf42be92..19af5242 100644
--- a/src/Output/DiffOnlyOutputBuilder.php
+++ b/src/Output/DiffOnlyOutputBuilder.php
@@ -7,9 +7,13 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
+use function fclose;
+use function fopen;
+use function fwrite;
+use function stream_get_contents;
+use function substr;
 use Localheinz\Diff\Differ;
 
 /**
@@ -30,38 +34,38 @@ public function __construct(string $header = "--- Original\n+++ New\n")
 
     public function getDiff(array $diff): string
     {
-        $buffer = \fopen('php://memory', 'r+b');
+        $buffer = fopen('php://memory', 'r+b');
 
         if ('' !== $this->header) {
-            \fwrite($buffer, $this->header);
+            fwrite($buffer, $this->header);
 
-            if ("\n" !== \substr($this->header, -1, 1)) {
-                \fwrite($buffer, "\n");
+            if ("\n" !== substr($this->header, -1, 1)) {
+                fwrite($buffer, "\n");
             }
         }
 
         foreach ($diff as $diffEntry) {
             if ($diffEntry[1] === Differ::ADDED) {
-                \fwrite($buffer, '+' . $diffEntry[0]);
+                fwrite($buffer, '+' . $diffEntry[0]);
             } elseif ($diffEntry[1] === Differ::REMOVED) {
-                \fwrite($buffer, '-' . $diffEntry[0]);
+                fwrite($buffer, '-' . $diffEntry[0]);
             } elseif ($diffEntry[1] === Differ::DIFF_LINE_END_WARNING) {
-                \fwrite($buffer, ' ' . $diffEntry[0]);
+                fwrite($buffer, ' ' . $diffEntry[0]);
 
                 continue; // Warnings should not be tested for line break, it will always be there
             } else { /* Not changed (old) 0 */
                 continue; // we didn't write the non changs line, so do not add a line break either
             }
 
-            $lc = \substr($diffEntry[0], -1);
+            $lc = substr($diffEntry[0], -1);
 
             if ($lc !== "\n" && $lc !== "\r") {
-                \fwrite($buffer, "\n"); // \No newline at end of file
+                fwrite($buffer, "\n"); // \No newline at end of file
             }
         }
 
-        $diff = \stream_get_contents($buffer, -1, 0);
-        \fclose($buffer);
+        $diff = stream_get_contents($buffer, -1, 0);
+        fclose($buffer);
 
         return $diff;
     }
diff --git a/src/Output/DiffOutputBuilderInterface.php b/src/Output/DiffOutputBuilderInterface.php
index dfba8714..d8cc9c4e 100644
--- a/src/Output/DiffOutputBuilderInterface.php
+++ b/src/Output/DiffOutputBuilderInterface.php
@@ -7,7 +7,6 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
 /**
diff --git a/src/Output/StrictUnifiedDiffOutputBuilder.php b/src/Output/StrictUnifiedDiffOutputBuilder.php
index e14e1b0f..433f1b41 100644
--- a/src/Output/StrictUnifiedDiffOutputBuilder.php
+++ b/src/Output/StrictUnifiedDiffOutputBuilder.php
@@ -7,9 +7,22 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
+use function array_merge;
+use function array_splice;
+use function count;
+use function fclose;
+use function fopen;
+use function fwrite;
+use function is_bool;
+use function is_int;
+use function is_string;
+use function max;
+use function min;
+use function sprintf;
+use function stream_get_contents;
+use function substr;
 use Localheinz\Diff\ConfigurationException;
 use Localheinz\Diff\Differ;
 
@@ -29,6 +42,7 @@ final class StrictUnifiedDiffOutputBuilder implements DiffOutputBuilderInterface
         'toFile'              => null,
         'toFileDate'          => null,
     ];
+
     /**
      * @var bool
      */
@@ -56,33 +70,26 @@ final class StrictUnifiedDiffOutputBuilder implements DiffOutputBuilderInterface
 
     public function __construct(array $options = [])
     {
-        $options = \array_merge(self::$default, $options);
+        $options = array_merge(self::$default, $options);
 
-        if (!\is_bool($options['collapseRanges'])) {
+        if (!is_bool($options['collapseRanges'])) {
             throw new ConfigurationException('collapseRanges', 'a bool', $options['collapseRanges']);
         }
 
-        if (!\is_int($options['contextLines']) || $options['contextLines'] < 0) {
+        if (!is_int($options['contextLines']) || $options['contextLines'] < 0) {
             throw new ConfigurationException('contextLines', 'an int >= 0', $options['contextLines']);
         }
 
-        if (!\is_int($options['commonLineThreshold']) || $options['commonLineThreshold'] <= 0) {
+        if (!is_int($options['commonLineThreshold']) || $options['commonLineThreshold'] <= 0) {
             throw new ConfigurationException('commonLineThreshold', 'an int > 0', $options['commonLineThreshold']);
         }
 
-        foreach (['fromFile', 'toFile'] as $option) {
-            if (!\is_string($options[$option])) {
-                throw new ConfigurationException($option, 'a string', $options[$option]);
-            }
-        }
-
-        foreach (['fromFileDate', 'toFileDate'] as $option) {
-            if (null !== $options[$option] && !\is_string($options[$option])) {
-                throw new ConfigurationException($option, 'a string or <null>', $options[$option]);
-            }
-        }
+        $this->assertString($options, 'fromFile');
+        $this->assertString($options, 'toFile');
+        $this->assertStringOrNull($options, 'fromFileDate');
+        $this->assertStringOrNull($options, 'toFileDate');
 
-        $this->header = \sprintf(
+        $this->header = sprintf(
             "--- %s%s\n+++ %s%s\n",
             $options['fromFile'],
             null === $options['fromFileDate'] ? '' : "\t" . $options['fromFileDate'],
@@ -97,48 +104,47 @@ public function __construct(array $options = [])
 
     public function getDiff(array $diff): string
     {
-        if (0 === \count($diff)) {
+        if (0 === count($diff)) {
             return '';
         }
 
         $this->changed = false;
 
-        $buffer = \fopen('php://memory', 'r+b');
-        \fwrite($buffer, $this->header);
+        $buffer = fopen('php://memory', 'r+b');
+        fwrite($buffer, $this->header);
 
         $this->writeDiffHunks($buffer, $diff);
 
         if (!$this->changed) {
-            \fclose($buffer);
+            fclose($buffer);
 
             return '';
         }
 
-        $diff = \stream_get_contents($buffer, -1, 0);
+        $diff = stream_get_contents($buffer, -1, 0);
 
-        \fclose($buffer);
+        fclose($buffer);
 
         // If the last char is not a linebreak: add it.
         // This might happen when both the `from` and `to` do not have a trailing linebreak
-        $last = \substr($diff, -1);
+        $last = substr($diff, -1);
 
         return "\n" !== $last && "\r" !== $last
             ? $diff . "\n"
-            : $diff
-        ;
+            : $diff;
     }
 
     private function writeDiffHunks($output, array $diff): void
     {
         // detect "No newline at end of file" and insert into `$diff` if needed
 
-        $upperLimit = \count($diff);
+        $upperLimit = count($diff);
 
         if (0 === $diff[$upperLimit - 1][1]) {
-            $lc = \substr($diff[$upperLimit - 1][0], -1);
+            $lc = substr($diff[$upperLimit - 1][0], -1);
 
             if ("\n" !== $lc) {
-                \array_splice($diff, $upperLimit, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
+                array_splice($diff, $upperLimit, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
             }
         } else {
             // search back for the last `+` and `-` line,
@@ -148,13 +154,13 @@ private function writeDiffHunks($output, array $diff): void
             for ($i = $upperLimit - 1; $i >= 0; --$i) {
                 if (isset($toFind[$diff[$i][1]])) {
                     unset($toFind[$diff[$i][1]]);
-                    $lc = \substr($diff[$i][0], -1);
+                    $lc = substr($diff[$i][0], -1);
 
                     if ("\n" !== $lc) {
-                        \array_splice($diff, $i + 1, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
+                        array_splice($diff, $i + 1, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
                     }
 
-                    if (!\count($toFind)) {
+                    if (!count($toFind)) {
                         break;
                     }
                 }
@@ -163,11 +169,13 @@ private function writeDiffHunks($output, array $diff): void
 
         // write hunks to output buffer
 
-        $cutOff      = \max($this->commonLineThreshold, $this->contextLines);
+        $cutOff      = max($this->commonLineThreshold, $this->contextLines);
         $hunkCapture = false;
         $sameCount   = $toRange = $fromRange = 0;
         $toStart     = $fromStart = 1;
+        $i           = 0;
 
+        /** @var int $i */
         foreach ($diff as $i => $entry) {
             if (0 === $entry[1]) { // same
                 if (false === $hunkCapture) {
@@ -184,8 +192,7 @@ private function writeDiffHunks($output, array $diff): void
                 if ($sameCount === $cutOff) {
                     $contextStartOffset = ($hunkCapture - $this->contextLines) < 0
                         ? $hunkCapture
-                        : $this->contextLines
-                    ;
+                        : $this->contextLines;
 
                     // note: $contextEndOffset = $this->contextLines;
                     //
@@ -249,12 +256,11 @@ private function writeDiffHunks($output, array $diff): void
 
         $contextStartOffset = $hunkCapture - $this->contextLines < 0
             ? $hunkCapture
-            : $this->contextLines
-        ;
+            : $this->contextLines;
 
         // prevent trying to write out more common lines than there are in the diff _and_
         // do not write more than configured through the context lines
-        $contextEndOffset = \min($sameCount, $this->contextLines);
+        $contextEndOffset = min($sameCount, $this->contextLines);
 
         $fromRange -= $sameCount;
         $toRange -= $sameCount;
@@ -281,32 +287,32 @@ private function writeHunk(
         int $toRange,
         $output
     ): void {
-        \fwrite($output, '@@ -' . $fromStart);
+        fwrite($output, '@@ -' . $fromStart);
 
         if (!$this->collapseRanges || 1 !== $fromRange) {
-            \fwrite($output, ',' . $fromRange);
+            fwrite($output, ',' . $fromRange);
         }
 
-        \fwrite($output, ' +' . $toStart);
+        fwrite($output, ' +' . $toStart);
 
         if (!$this->collapseRanges || 1 !== $toRange) {
-            \fwrite($output, ',' . $toRange);
+            fwrite($output, ',' . $toRange);
         }
 
-        \fwrite($output, " @@\n");
+        fwrite($output, " @@\n");
 
         for ($i = $diffStartIndex; $i < $diffEndIndex; ++$i) {
             if ($diff[$i][1] === Differ::ADDED) {
                 $this->changed = true;
-                \fwrite($output, '+' . $diff[$i][0]);
+                fwrite($output, '+' . $diff[$i][0]);
             } elseif ($diff[$i][1] === Differ::REMOVED) {
                 $this->changed = true;
-                \fwrite($output, '-' . $diff[$i][0]);
+                fwrite($output, '-' . $diff[$i][0]);
             } elseif ($diff[$i][1] === Differ::OLD) {
-                \fwrite($output, ' ' . $diff[$i][0]);
+                fwrite($output, ' ' . $diff[$i][0]);
             } elseif ($diff[$i][1] === Differ::NO_LINE_END_EOF_WARNING) {
                 $this->changed = true;
-                \fwrite($output, $diff[$i][0]);
+                fwrite($output, $diff[$i][0]);
             }
             //} elseif ($diff[$i][1] === Differ::DIFF_LINE_END_WARNING) { // custom comment inserted by PHPUnit/diff package
                 //  skip
@@ -315,4 +321,18 @@ private function writeHunk(
             //}
         }
     }
+
+    private function assertString(array $options, string $option): void
+    {
+        if (!is_string($options[$option])) {
+            throw new ConfigurationException($option, 'a string', $options[$option]);
+        }
+    }
+
+    private function assertStringOrNull(array $options, string $option): void
+    {
+        if (null !== $options[$option] && !is_string($options[$option])) {
+            throw new ConfigurationException($option, 'a string or <null>', $options[$option]);
+        }
+    }
 }
diff --git a/src/Output/UnifiedDiffOutputBuilder.php b/src/Output/UnifiedDiffOutputBuilder.php
index 7b609f3e..050fc251 100644
--- a/src/Output/UnifiedDiffOutputBuilder.php
+++ b/src/Output/UnifiedDiffOutputBuilder.php
@@ -7,9 +7,18 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
+use function array_splice;
+use function count;
+use function fclose;
+use function fopen;
+use function fwrite;
+use function max;
+use function min;
+use function stream_get_contents;
+use function strlen;
+use function substr;
 use Localheinz\Diff\Differ;
 
 /**
@@ -50,45 +59,44 @@ public function __construct(string $header = "--- Original\n+++ New\n", bool $ad
 
     public function getDiff(array $diff): string
     {
-        $buffer = \fopen('php://memory', 'r+b');
+        $buffer = fopen('php://memory', 'r+b');
 
         if ('' !== $this->header) {
-            \fwrite($buffer, $this->header);
+            fwrite($buffer, $this->header);
 
-            if ("\n" !== \substr($this->header, -1, 1)) {
-                \fwrite($buffer, "\n");
+            if ("\n" !== substr($this->header, -1, 1)) {
+                fwrite($buffer, "\n");
             }
         }
 
-        if (0 !== \count($diff)) {
+        if (0 !== count($diff)) {
             $this->writeDiffHunks($buffer, $diff);
         }
 
-        $diff = \stream_get_contents($buffer, -1, 0);
+        $diff = stream_get_contents($buffer, -1, 0);
 
-        \fclose($buffer);
+        fclose($buffer);
 
-        // If the last char is not a linebreak: add it.
+        // If the diff is non-empty and last char is not a linebreak: add it.
         // This might happen when both the `from` and `to` do not have a trailing linebreak
-        $last = \substr($diff, -1);
+        $last = substr($diff, -1);
 
-        return "\n" !== $last && "\r" !== $last
+        return 0 !== strlen($diff) && "\n" !== $last && "\r" !== $last
             ? $diff . "\n"
-            : $diff
-        ;
+            : $diff;
     }
 
     private function writeDiffHunks($output, array $diff): void
     {
         // detect "No newline at end of file" and insert into `$diff` if needed
 
-        $upperLimit = \count($diff);
+        $upperLimit = count($diff);
 
         if (0 === $diff[$upperLimit - 1][1]) {
-            $lc = \substr($diff[$upperLimit - 1][0], -1);
+            $lc = substr($diff[$upperLimit - 1][0], -1);
 
             if ("\n" !== $lc) {
-                \array_splice($diff, $upperLimit, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
+                array_splice($diff, $upperLimit, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
             }
         } else {
             // search back for the last `+` and `-` line,
@@ -98,13 +106,13 @@ private function writeDiffHunks($output, array $diff): void
             for ($i = $upperLimit - 1; $i >= 0; --$i) {
                 if (isset($toFind[$diff[$i][1]])) {
                     unset($toFind[$diff[$i][1]]);
-                    $lc = \substr($diff[$i][0], -1);
+                    $lc = substr($diff[$i][0], -1);
 
                     if ("\n" !== $lc) {
-                        \array_splice($diff, $i + 1, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
+                        array_splice($diff, $i + 1, 0, [["\n\\ No newline at end of file\n", Differ::NO_LINE_END_EOF_WARNING]]);
                     }
 
-                    if (!\count($toFind)) {
+                    if (!count($toFind)) {
                         break;
                     }
                 }
@@ -113,11 +121,13 @@ private function writeDiffHunks($output, array $diff): void
 
         // write hunks to output buffer
 
-        $cutOff      = \max($this->commonLineThreshold, $this->contextLines);
+        $cutOff      = max($this->commonLineThreshold, $this->contextLines);
         $hunkCapture = false;
         $sameCount   = $toRange   = $fromRange = 0;
         $toStart     = $fromStart = 1;
+        $i           = 0;
 
+        /** @var int $i */
         foreach ($diff as $i => $entry) {
             if (0 === $entry[1]) { // same
                 if (false === $hunkCapture) {
@@ -134,8 +144,7 @@ private function writeDiffHunks($output, array $diff): void
                 if ($sameCount === $cutOff) {
                     $contextStartOffset = ($hunkCapture - $this->contextLines) < 0
                         ? $hunkCapture
-                        : $this->contextLines
-                    ;
+                        : $this->contextLines;
 
                     // note: $contextEndOffset = $this->contextLines;
                     //
@@ -197,12 +206,11 @@ private function writeDiffHunks($output, array $diff): void
 
         $contextStartOffset = $hunkCapture - $this->contextLines < 0
             ? $hunkCapture
-            : $this->contextLines
-        ;
+            : $this->contextLines;
 
         // prevent trying to write out more common lines than there are in the diff _and_
         // do not write more than configured through the context lines
-        $contextEndOffset = \min($sameCount, $this->contextLines);
+        $contextEndOffset = min($sameCount, $this->contextLines);
 
         $fromRange -= $sameCount;
         $toRange -= $sameCount;
@@ -230,34 +238,34 @@ private function writeHunk(
         $output
     ): void {
         if ($this->addLineNumbers) {
-            \fwrite($output, '@@ -' . $fromStart);
+            fwrite($output, '@@ -' . $fromStart);
 
             if (!$this->collapseRanges || 1 !== $fromRange) {
-                \fwrite($output, ',' . $fromRange);
+                fwrite($output, ',' . $fromRange);
             }
 
-            \fwrite($output, ' +' . $toStart);
+            fwrite($output, ' +' . $toStart);
 
             if (!$this->collapseRanges || 1 !== $toRange) {
-                \fwrite($output, ',' . $toRange);
+                fwrite($output, ',' . $toRange);
             }
 
-            \fwrite($output, " @@\n");
+            fwrite($output, " @@\n");
         } else {
-            \fwrite($output, "@@ @@\n");
+            fwrite($output, "@@ @@\n");
         }
 
         for ($i = $diffStartIndex; $i < $diffEndIndex; ++$i) {
             if ($diff[$i][1] === Differ::ADDED) {
-                \fwrite($output, '+' . $diff[$i][0]);
+                fwrite($output, '+' . $diff[$i][0]);
             } elseif ($diff[$i][1] === Differ::REMOVED) {
-                \fwrite($output, '-' . $diff[$i][0]);
+                fwrite($output, '-' . $diff[$i][0]);
             } elseif ($diff[$i][1] === Differ::OLD) {
-                \fwrite($output, ' ' . $diff[$i][0]);
+                fwrite($output, ' ' . $diff[$i][0]);
             } elseif ($diff[$i][1] === Differ::NO_LINE_END_EOF_WARNING) {
-                \fwrite($output, "\n"); // $diff[$i][0]
+                fwrite($output, "\n"); // $diff[$i][0]
             } else { /* Not changed (old) Differ::OLD or Warning Differ::DIFF_LINE_END_WARNING */
-                \fwrite($output, ' ' . $diff[$i][0]);
+                fwrite($output, ' ' . $diff[$i][0]);
             }
         }
     }
diff --git a/src/Parser.php b/src/Parser.php
index 3a2bb3db..9974ec36 100644
--- a/src/Parser.php
+++ b/src/Parser.php
@@ -7,35 +7,38 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
+use function array_pop;
+use function count;
+use function max;
+use function preg_match;
+use function preg_split;
+
 /**
  * Unified diff parser.
  */
 final class Parser
 {
     /**
-     * @param string $string
-     *
      * @return Diff[]
      */
     public function parse(string $string): array
     {
-        $lines = \preg_split('(\r\n|\r|\n)', $string);
+        $lines = preg_split('(\r\n|\r|\n)', $string);
 
-        if (!empty($lines) && $lines[\count($lines) - 1] === '') {
-            \array_pop($lines);
+        if (!empty($lines) && $lines[count($lines) - 1] === '') {
+            array_pop($lines);
         }
 
-        $lineCount = \count($lines);
+        $lineCount = count($lines);
         $diffs     = [];
         $diff      = null;
         $collected = [];
 
         for ($i = 0; $i < $lineCount; ++$i) {
-            if (\preg_match('(^---\\s+(?P<file>\\S+))', $lines[$i], $fromMatch) &&
-                \preg_match('(^\\+\\+\\+\\s+(?P<file>\\S+))', $lines[$i + 1], $toMatch)) {
+            if (preg_match('(^---\\s+(?P<file>\\S+))', $lines[$i], $fromMatch) &&
+                preg_match('(^\\+\\+\\+\\s+(?P<file>\\S+))', $lines[$i + 1], $toMatch)) {
                 if ($diff !== null) {
                     $this->parseFileDiff($diff, $collected);
 
@@ -47,7 +50,7 @@ public function parse(string $string): array
 
                 ++$i;
             } else {
-                if (\preg_match('/^(?:diff --git |index [\da-f\.]+|[+-]{3} [ab])/', $lines[$i])) {
+                if (preg_match('/^(?:diff --git |index [\da-f\.]+|[+-]{3} [ab])/', $lines[$i])) {
                     continue;
                 }
 
@@ -55,7 +58,7 @@ public function parse(string $string): array
             }
         }
 
-        if ($diff !== null && \count($collected)) {
+        if ($diff !== null && count($collected)) {
             $this->parseFileDiff($diff, $collected);
 
             $diffs[] = $diff;
@@ -66,16 +69,17 @@ public function parse(string $string): array
 
     private function parseFileDiff(Diff $diff, array $lines): void
     {
-        $chunks = [];
-        $chunk  = null;
+        $chunks    = [];
+        $chunk     = null;
+        $diffLines = [];
 
         foreach ($lines as $line) {
-            if (\preg_match('/^@@\s+-(?P<start>\d+)(?:,\s*(?P<startrange>\d+))?\s+\+(?P<end>\d+)(?:,\s*(?P<endrange>\d+))?\s+@@/', $line, $match)) {
+            if (preg_match('/^@@\s+-(?P<start>\d+)(?:,\s*(?P<startrange>\d+))?\s+\+(?P<end>\d+)(?:,\s*(?P<endrange>\d+))?\s+@@/', $line, $match)) {
                 $chunk = new Chunk(
                     (int) $match['start'],
-                    isset($match['startrange']) ? \max(1, (int) $match['startrange']) : 1,
+                    isset($match['startrange']) ? max(1, (int) $match['startrange']) : 1,
                     (int) $match['end'],
-                    isset($match['endrange']) ? \max(1, (int) $match['endrange']) : 1
+                    isset($match['endrange']) ? max(1, (int) $match['endrange']) : 1
                 );
 
                 $chunks[]  = $chunk;
@@ -84,7 +88,7 @@ private function parseFileDiff(Diff $diff, array $lines): void
                 continue;
             }
 
-            if (\preg_match('/^(?P<type>[+ -])?(?P<line>.*)/', $line, $match)) {
+            if (preg_match('/^(?P<type>[+ -])?(?P<line>.*)/', $line, $match)) {
                 $type = Line::UNCHANGED;
 
                 if ($match['type'] === '+') {
diff --git a/src/TimeEfficientLongestCommonSubsequenceCalculator.php b/src/TimeEfficientLongestCommonSubsequenceCalculator.php
index f740566c..6acd2769 100644
--- a/src/TimeEfficientLongestCommonSubsequenceCalculator.php
+++ b/src/TimeEfficientLongestCommonSubsequenceCalculator.php
@@ -7,9 +7,13 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
+use function array_reverse;
+use function count;
+use function max;
+use SplFixedArray;
+
 final class TimeEfficientLongestCommonSubsequenceCalculator implements LongestCommonSubsequenceCalculator
 {
     /**
@@ -18,10 +22,10 @@ final class TimeEfficientLongestCommonSubsequenceCalculator implements LongestCo
     public function calculate(array $from, array $to): array
     {
         $common     = [];
-        $fromLength = \count($from);
-        $toLength   = \count($to);
+        $fromLength = count($from);
+        $toLength   = count($to);
         $width      = $fromLength + 1;
-        $matrix     = new \SplFixedArray($width * ($toLength + 1));
+        $matrix     = new SplFixedArray($width * ($toLength + 1));
 
         for ($i = 0; $i <= $fromLength; ++$i) {
             $matrix[$i] = 0;
@@ -34,7 +38,7 @@ public function calculate(array $from, array $to): array
         for ($i = 1; $i <= $fromLength; ++$i) {
             for ($j = 1; $j <= $toLength; ++$j) {
                 $o          = ($j * $width) + $i;
-                $matrix[$o] = \max(
+                $matrix[$o] = max(
                     $matrix[$o - 1],
                     $matrix[$o - $width],
                     $from[$i - 1] === $to[$j - 1] ? $matrix[$o - $width - 1] + 1 : 0
@@ -61,6 +65,6 @@ public function calculate(array $from, array $to): array
             }
         }
 
-        return \array_reverse($common);
+        return array_reverse($common);
     }
 }
diff --git a/tests/ChunkTest.php b/tests/ChunkTest.php
index f61f2e3f..18385cb3 100644
--- a/tests/ChunkTest.php
+++ b/tests/ChunkTest.php
@@ -7,15 +7,14 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 use PHPUnit\Framework\TestCase;
 
 /**
- * @covers Localheinz\Diff\Chunk
+ * @covers \Localheinz\Diff\Chunk
  *
- * @uses Localheinz\Diff\Line
+ * @uses \Localheinz\Diff\Line
  */
 final class ChunkTest extends TestCase
 {
diff --git a/tests/DiffTest.php b/tests/DiffTest.php
index 4c0dfece..f85fe66d 100644
--- a/tests/DiffTest.php
+++ b/tests/DiffTest.php
@@ -7,15 +7,14 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 use PHPUnit\Framework\TestCase;
 
 /**
- * @covers Localheinz\Diff\Diff
+ * @covers \Localheinz\Diff\Diff
  *
- * @uses Localheinz\Diff\Chunk
+ * @uses \Localheinz\Diff\Chunk
  */
 final class DiffTest extends TestCase
 {
diff --git a/tests/DifferTest.php b/tests/DifferTest.php
index c714dfe4..05ab9405 100644
--- a/tests/DifferTest.php
+++ b/tests/DifferTest.php
@@ -7,19 +7,20 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 use PHPUnit\Framework\TestCase;
-use Localheinz\Diff\Output\UnifiedDiffOutputBuilder;
+use ReflectionObject;
+use SplFileInfo;
+use stdClass;
 
 /**
- * @covers Localheinz\Diff\Differ
- * @covers Localheinz\Diff\Output\UnifiedDiffOutputBuilder
+ * @covers \Localheinz\Diff\Differ
+ * @covers \Localheinz\Diff\Output\UnifiedDiffOutputBuilder
  *
- * @uses Localheinz\Diff\MemoryEfficientLongestCommonSubsequenceCalculator
- * @uses Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
- * @uses Localheinz\Diff\Output\AbstractChunkOutputBuilder
+ * @uses \Localheinz\Diff\MemoryEfficientLongestCommonSubsequenceCalculator
+ * @uses \Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
+ * @uses \Localheinz\Diff\Output\AbstractChunkOutputBuilder
  */
 final class DifferTest extends TestCase
 {
@@ -34,7 +35,6 @@ protected function setUp(): void
     }
 
     /**
-     * @param array        $expected
      * @param array|string $from
      * @param array|string $to
      *
@@ -46,10 +46,6 @@ public function testArrayRepresentationOfDiffCanBeRenderedUsingTimeEfficientLcsI
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     *
      * @dataProvider textProvider
      */
     public function testTextRepresentationOfDiffCanBeRenderedUsingTimeEfficientLcsImplementation(string $expected, string $from, string $to): void
@@ -58,7 +54,6 @@ public function testTextRepresentationOfDiffCanBeRenderedUsingTimeEfficientLcsIm
     }
 
     /**
-     * @param array        $expected
      * @param array|string $from
      * @param array|string $to
      *
@@ -70,10 +65,6 @@ public function testArrayRepresentationOfDiffCanBeRenderedUsingMemoryEfficientLc
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     *
      * @dataProvider textProvider
      */
     public function testTextRepresentationOfDiffCanBeRenderedUsingMemoryEfficientLcsImplementation(string $expected, string $from, string $to): void
@@ -296,7 +287,7 @@ public function textProvider(): array
  k
 
 EOF
-            ,
+                ,
                 "a\nb\nc\nd\ne\nf\ng\nh\ni\nj\nk\n",
                 "a\np\nc\nd\ne\nf\ng\nh\ni\nw\nk\n",
             ],
@@ -312,7 +303,7 @@ public function textProvider(): array
  3
 
 EOF
-            ,
+                ,
                 "A\n1\n2\n3\n4\n5\n6\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n",
                 "B\n1\n2\n3\n4\n5\n6\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n1\n",
             ],
@@ -342,18 +333,15 @@ public function testDiffInvalidToType(): void
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessageRegExp('#^"to" must be an array or string\.$#');
 
-        $this->differ->diffToArray('', new \stdClass);
+        $this->differ->diffToArray('', new stdClass);
     }
 
     /**
-     * @param array  $expected
-     * @param string $input
-     *
      * @dataProvider provideSplitStringByLinesCases
      */
     public function testSplitStringByLines(array $expected, string $input): void
     {
-        $reflection = new \ReflectionObject($this->differ);
+        $reflection = new ReflectionObject($this->differ);
         $method     = $reflection->getMethod('splitStringByLines');
         $method->setAccessible(true);
 
@@ -439,6 +427,6 @@ public function testConstructorInvalidArgObject(): void
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessageRegExp('/^Expected builder to be an instance of DiffOutputBuilderInterface, <null> or a string, got instance of "SplFileInfo"\.$/');
 
-        new Differ(new \SplFileInfo(__FILE__));
+        new Differ(new SplFileInfo(__FILE__));
     }
 }
diff --git a/tests/Exception/ConfigurationExceptionTest.php b/tests/Exception/ConfigurationExceptionTest.php
index e7fa1f41..ce4f3eaf 100644
--- a/tests/Exception/ConfigurationExceptionTest.php
+++ b/tests/Exception/ConfigurationExceptionTest.php
@@ -7,13 +7,14 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
+use BadMethodCallException;
 use PHPUnit\Framework\TestCase;
+use SplFileInfo;
 
 /**
- * @covers Localheinz\Diff\ConfigurationException
+ * @covers \Localheinz\Diff\ConfigurationException
  */
 final class ConfigurationExceptionTest extends TestCase
 {
@@ -31,9 +32,9 @@ public function testConstruct(): void
         $e = new ConfigurationException(
             'test',
             'integer',
-            new \SplFileInfo(__FILE__),
+            new SplFileInfo(__FILE__),
             789,
-            new \BadMethodCallException(__METHOD__)
+            new BadMethodCallException(__METHOD__)
         );
 
         $this->assertSame('Option "test" must be integer, got "SplFileInfo".', $e->getMessage());
diff --git a/tests/Exception/InvalidArgumentExceptionTest.php b/tests/Exception/InvalidArgumentExceptionTest.php
index 4a7a85a4..e1bf7087 100644
--- a/tests/Exception/InvalidArgumentExceptionTest.php
+++ b/tests/Exception/InvalidArgumentExceptionTest.php
@@ -7,19 +7,19 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
+use LogicException;
 use PHPUnit\Framework\TestCase;
 
 /**
- * @covers Localheinz\Diff\InvalidArgumentException
+ * @covers \Localheinz\Diff\InvalidArgumentException
  */
 final class InvalidArgumentExceptionTest extends TestCase
 {
     public function testInvalidArgumentException(): void
     {
-        $previousException = new \LogicException();
+        $previousException = new LogicException();
         $message           = 'test';
         $code              = 123;
 
diff --git a/tests/LineTest.php b/tests/LineTest.php
index 88b2661d..9c7ca255 100644
--- a/tests/LineTest.php
+++ b/tests/LineTest.php
@@ -7,13 +7,12 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 use PHPUnit\Framework\TestCase;
 
 /**
- * @covers Localheinz\Diff\Line
+ * @covers \Localheinz\Diff\Line
  */
 final class LineTest extends TestCase
 {
diff --git a/tests/LongestCommonSubsequenceTest.php b/tests/LongestCommonSubsequenceTest.php
index deea9a35..db5923c4 100644
--- a/tests/LongestCommonSubsequenceTest.php
+++ b/tests/LongestCommonSubsequenceTest.php
@@ -7,9 +7,13 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
+use function array_reverse;
+use function array_slice;
+use function ini_get;
+use function ini_set;
+use function range;
 use PHPUnit\Framework\TestCase;
 
 /**
@@ -34,15 +38,15 @@ abstract class LongestCommonSubsequenceTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->memoryLimit = \ini_get('memory_limit');
-        \ini_set('memory_limit', '-1');
+        $this->memoryLimit = ini_get('memory_limit');
+        ini_set('memory_limit', '-1');
 
         $this->implementation = $this->createImplementation();
     }
 
     protected function tearDown(): void
     {
-        \ini_set('memory_limit', $this->memoryLimit);
+        ini_set('memory_limit', $this->memoryLimit);
     }
 
     public function testBothEmpty(): void
@@ -83,7 +87,7 @@ public function testIsStrictComparison(): void
     public function testEqualSequences(): void
     {
         foreach ($this->stress_sizes as $size) {
-            $range  = \range(1, $size);
+            $range  = range(1, $size);
             $from   = $range;
             $to     = $range;
             $common = $this->implementation->calculate($from, $to);
@@ -105,8 +109,8 @@ public function testDistinctSequences(): void
         $this->assertSame([], $common);
 
         foreach ($this->stress_sizes as $size) {
-            $from   = \range(1, $size);
-            $to     = \range($size + 1, $size * 2);
+            $from   = range(1, $size);
+            $to     = range($size + 1, $size * 2);
             $common = $this->implementation->calculate($from, $to);
             $this->assertSame([], $common);
         }
@@ -127,9 +131,9 @@ public function testCommonSubsequence(): void
         $this->assertSame($expected, $common);
 
         foreach ($this->stress_sizes as $size) {
-            $from     = $size < 2 ? [1] : \range(1, $size + 1, 2);
-            $to       = $size < 3 ? [1] : \range(1, $size + 1, 3);
-            $expected = $size < 6 ? [1] : \range(1, $size + 1, 6);
+            $from     = $size < 2 ? [1] : range(1, $size + 1, 2);
+            $to       = $size < 3 ? [1] : range(1, $size + 1, 3);
+            $expected = $size < 6 ? [1] : range(1, $size + 1, 6);
             $common   = $this->implementation->calculate($from, $to);
 
             $this->assertSame($expected, $common);
@@ -139,8 +143,8 @@ public function testCommonSubsequence(): void
     public function testSingleElementSubsequenceAtStart(): void
     {
         foreach ($this->stress_sizes as $size) {
-            $from   = \range(1, $size);
-            $to     = \array_slice($from, 0, 1);
+            $from   = range(1, $size);
+            $to     = array_slice($from, 0, 1);
             $common = $this->implementation->calculate($from, $to);
 
             $this->assertSame($to, $common);
@@ -150,8 +154,8 @@ public function testSingleElementSubsequenceAtStart(): void
     public function testSingleElementSubsequenceAtMiddle(): void
     {
         foreach ($this->stress_sizes as $size) {
-            $from   = \range(1, $size);
-            $to     = \array_slice($from, (int) ($size / 2), 1);
+            $from   = range(1, $size);
+            $to     = array_slice($from, (int) ($size / 2), 1);
             $common = $this->implementation->calculate($from, $to);
 
             $this->assertSame($to, $common);
@@ -161,8 +165,8 @@ public function testSingleElementSubsequenceAtMiddle(): void
     public function testSingleElementSubsequenceAtEnd(): void
     {
         foreach ($this->stress_sizes as $size) {
-            $from   = \range(1, $size);
-            $to     = \array_slice($from, $size - 1, 1);
+            $from   = range(1, $size);
+            $to     = array_slice($from, $size - 1, 1);
             $common = $this->implementation->calculate($from, $to);
 
             $this->assertSame($to, $common);
@@ -178,8 +182,8 @@ public function testReversedSequences(): void
         $this->assertSame($expected, $common);
 
         foreach ($this->stress_sizes as $size) {
-            $from   = \range(1, $size);
-            $to     = \array_reverse($from);
+            $from   = range(1, $size);
+            $to     = array_reverse($from);
             $common = $this->implementation->calculate($from, $to);
 
             $this->assertSame([1], $common);
@@ -194,8 +198,5 @@ public function testStrictTypeCalculate(): void
         $this->assertCount(0, $diff);
     }
 
-    /**
-     * @return LongestCommonSubsequenceCalculator
-     */
     abstract protected function createImplementation(): LongestCommonSubsequenceCalculator;
 }
diff --git a/tests/MemoryEfficientImplementationTest.php b/tests/MemoryEfficientImplementationTest.php
index 1d7797f3..3fd133d3 100644
--- a/tests/MemoryEfficientImplementationTest.php
+++ b/tests/MemoryEfficientImplementationTest.php
@@ -7,11 +7,10 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 /**
- * @covers Localheinz\Diff\MemoryEfficientLongestCommonSubsequenceCalculator
+ * @covers \Localheinz\Diff\MemoryEfficientLongestCommonSubsequenceCalculator
  */
 final class MemoryEfficientImplementationTest extends LongestCommonSubsequenceTest
 {
diff --git a/tests/Output/AbstractChunkOutputBuilderTest.php b/tests/Output/AbstractChunkOutputBuilderTest.php
index 443d2a44..29454607 100644
--- a/tests/Output/AbstractChunkOutputBuilderTest.php
+++ b/tests/Output/AbstractChunkOutputBuilderTest.php
@@ -7,27 +7,21 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
-use PHPUnit\Framework\TestCase;
 use Localheinz\Diff\Differ;
+use PHPUnit\Framework\TestCase;
 
 /**
- * @covers Localheinz\Diff\Output\AbstractChunkOutputBuilder
+ * @covers \Localheinz\Diff\Output\AbstractChunkOutputBuilder
  *
- * @uses Localheinz\Diff\Differ
- * @uses Localheinz\Diff\Output\UnifiedDiffOutputBuilder
- * @uses Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
+ * @uses \Localheinz\Diff\Differ
+ * @uses \Localheinz\Diff\Output\UnifiedDiffOutputBuilder
+ * @uses \Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
  */
 final class AbstractChunkOutputBuilderTest extends TestCase
 {
     /**
-     * @param array  $expected
-     * @param string $from
-     * @param string $to
-     * @param int    $lineThreshold
-     *
      * @dataProvider provideGetCommonChunks
      */
     public function testGetCommonChunks(array $expected, string $from, string $to, int $lineThreshold = 5): void
diff --git a/tests/Output/DiffOnlyOutputBuilderTest.php b/tests/Output/DiffOnlyOutputBuilderTest.php
index 72f8e81c..9ff43a11 100644
--- a/tests/Output/DiffOnlyOutputBuilderTest.php
+++ b/tests/Output/DiffOnlyOutputBuilderTest.php
@@ -7,26 +7,20 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
-use PHPUnit\Framework\TestCase;
 use Localheinz\Diff\Differ;
+use PHPUnit\Framework\TestCase;
 
 /**
- * @covers Localheinz\Diff\Output\DiffOnlyOutputBuilder
+ * @covers \Localheinz\Diff\Output\DiffOnlyOutputBuilder
  *
- * @uses Localheinz\Diff\Differ
- * @uses Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
+ * @uses \Localheinz\Diff\Differ
+ * @uses \Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
  */
 final class DiffOnlyOutputBuilderTest extends TestCase
 {
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     * @param string $header
-     *
      * @dataProvider textForNoNonDiffLinesProvider
      */
     public function testDiffDoNotShowNonDiffLines(string $expected, string $from, string $to, string $header = ''): void
diff --git a/tests/Output/Integration/StrictUnifiedDiffOutputBuilderIntegrationTest.php b/tests/Output/Integration/StrictUnifiedDiffOutputBuilderIntegrationTest.php
index 97a89f27..0bd1107c 100644
--- a/tests/Output/Integration/StrictUnifiedDiffOutputBuilderIntegrationTest.php
+++ b/tests/Output/Integration/StrictUnifiedDiffOutputBuilderIntegrationTest.php
@@ -7,21 +7,34 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
-use PHPUnit\Framework\TestCase;
+use const PREG_SPLIT_DELIM_CAPTURE;
+use const PREG_SPLIT_NO_EMPTY;
+use function file_put_contents;
+use function implode;
+use function is_dir;
+use function preg_replace;
+use function preg_split;
+use function realpath;
+use function sprintf;
+use function unlink;
 use Localheinz\Diff\Differ;
 use Localheinz\Diff\Utils\FileUtils;
 use Localheinz\Diff\Utils\UnifiedDiffAssertTrait;
+use PHPUnit\Framework\TestCase;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use RuntimeException;
+use SplFileInfo;
 use Symfony\Component\Process\Process;
 
 /**
- * @covers Localheinz\Diff\Output\StrictUnifiedDiffOutputBuilder
+ * @covers \Localheinz\Diff\Output\StrictUnifiedDiffOutputBuilder
  *
- * @uses Localheinz\Diff\Differ
- * @uses Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
- * @uses Localheinz\Diff\MemoryEfficientLongestCommonSubsequenceCalculator
+ * @uses \Localheinz\Diff\Differ
+ * @uses \Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
+ * @uses \Localheinz\Diff\MemoryEfficientLongestCommonSubsequenceCalculator
  *
  * @requires OS Linux
  */
@@ -39,13 +52,13 @@ final class StrictUnifiedDiffOutputBuilderIntegrationTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->dir       = \realpath(__DIR__ . '/../../fixtures/out') . '/';
+        $this->dir       = realpath(__DIR__ . '/../../fixtures/out') . '/';
         $this->fileFrom  = $this->dir . 'from.txt';
         $this->fileTo    = $this->dir . 'to.txt';
         $this->filePatch = $this->dir . 'diff.patch';
 
-        if (!\is_dir($this->dir)) {
-            throw new \RuntimeException('Integration test working directory not found.');
+        if (!is_dir($this->dir)) {
+            throw new RuntimeException('Integration test working directory not found.');
         }
 
         $this->cleanUpTempFiles();
@@ -57,16 +70,13 @@ protected function tearDown(): void
     }
 
     /**
-     * Integration test
+     * Integration test.
      *
      * - get a file pair
      * - create a `diff` between the files
      * - test applying the diff using `git apply`
      * - test applying the diff using `patch`
      *
-     * @param string $fileFrom
-     * @param string $fileTo
-     *
      * @dataProvider provideFilePairs
      */
     public function testIntegrationUsingPHPFileInVendorGitApply(string $fileFrom, string $fileTo): void
@@ -87,16 +97,13 @@ public function testIntegrationUsingPHPFileInVendorGitApply(string $fileFrom, st
     }
 
     /**
-     * Integration test
+     * Integration test.
      *
      * - get a file pair
      * - create a `diff` between the files
      * - test applying the diff using `git apply`
      * - test applying the diff using `patch`
      *
-     * @param string $fileFrom
-     * @param string $fileTo
-     *
      * @dataProvider provideFilePairs
      */
     public function testIntegrationUsingPHPFileInVendorPatch(string $fileFrom, string $fileTo): void
@@ -117,10 +124,6 @@ public function testIntegrationUsingPHPFileInVendorPatch(string $fileFrom, strin
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     *
      * @dataProvider provideOutputBuildingCases
      * @dataProvider provideSample
      * @dataProvider provideBasicDiffGeneration
@@ -131,10 +134,6 @@ public function testIntegrationOfUnitTestCasesGitApply(string $expected, string
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     *
      * @dataProvider provideOutputBuildingCases
      * @dataProvider provideSample
      * @dataProvider provideBasicDiffGeneration
@@ -163,18 +162,18 @@ public function provideFilePairs(): array
     {
         $cases     = [];
         $fromFile  = __FILE__;
-        $vendorDir = \realpath(__DIR__ . '/../../../vendor');
+        $vendorDir = realpath(__DIR__ . '/../../../vendor');
 
-        $fileIterator = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($vendorDir, \RecursiveDirectoryIterator::SKIP_DOTS));
+        $fileIterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($vendorDir, RecursiveDirectoryIterator::SKIP_DOTS));
 
-        /** @var \SplFileInfo $file */
+        /** @var SplFileInfo $file */
         foreach ($fileIterator as $file) {
             if ('php' !== $file->getExtension()) {
                 continue;
             }
 
             $toFile                                                                                         = $file->getPathname();
-            $cases[\sprintf("Diff file:\n\"%s\"\nvs.\n\"%s\"\n", \realpath($fromFile), \realpath($toFile))] = [$fromFile, $toFile];
+            $cases[sprintf("Diff file:\n\"%s\"\nvs.\n\"%s\"\n", realpath($fromFile), realpath($toFile))]    = [$fromFile, $toFile];
             $fromFile                                                                                       = $toFile;
         }
 
@@ -184,10 +183,6 @@ public function provideFilePairs(): array
     /**
      * Compare diff create by builder and against one create by `diff` command.
      *
-     * @param string $diff
-     * @param string $from
-     * @param string $to
-     *
      * @dataProvider provideBasicDiffGeneration
      */
     public function testIntegrationDiffOutputBuilderVersusDiffCommand(string $diff, string $from, string $to): void
@@ -195,24 +190,31 @@ public function testIntegrationDiffOutputBuilderVersusDiffCommand(string $diff,
         $this->assertNotSame('', $diff);
         $this->assertValidUnifiedDiffFormat($diff);
 
-        $this->assertNotFalse(\file_put_contents($this->fileFrom, $from));
-        $this->assertNotFalse(\file_put_contents($this->fileTo, $to));
+        $this->assertNotFalse(file_put_contents($this->fileFrom, $from));
+        $this->assertNotFalse(file_put_contents($this->fileTo, $to));
+
+        $p = Process::fromShellCommandline('diff -u $from $to');
+        $p->run(
+            null,
+            [
+                'from' => $this->fileFrom,
+                'to'   => $this->fileTo,
+            ]
+        );
 
-        $p = new Process(\sprintf('diff -u %s %s', \escapeshellarg($this->fileFrom), \escapeshellarg($this->fileTo)));
-        $p->run();
         $this->assertSame(1, $p->getExitCode()); // note: Process assumes exit code 0 for `isSuccessful`, however `diff` uses the exit code `1` for success with diff
 
         $output = $p->getOutput();
 
-        $diffLines    = \preg_split('/(.*\R)/', $diff, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
-        $diffLines[0] = \preg_replace('#^\-\-\- .*#', '--- /' . $this->fileFrom, $diffLines[0], 1);
-        $diffLines[1] = \preg_replace('#^\+\+\+ .*#', '+++ /' . $this->fileFrom, $diffLines[1], 1);
-        $diff         = \implode('', $diffLines);
+        $diffLines    = preg_split('/(.*\R)/', $diff, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
+        $diffLines[0] = preg_replace('#^\-\-\- .*#', '--- /' . $this->fileFrom, $diffLines[0], 1);
+        $diffLines[1] = preg_replace('#^\+\+\+ .*#', '+++ /' . $this->fileFrom, $diffLines[1], 1);
+        $diff         = implode('', $diffLines);
 
-        $outputLines    = \preg_split('/(.*\R)/', $output, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
-        $outputLines[0] = \preg_replace('#^\-\-\- .*#', '--- /' . $this->fileFrom, $outputLines[0], 1);
-        $outputLines[1] = \preg_replace('#^\+\+\+ .*#', '+++ /' . $this->fileFrom, $outputLines[1], 1);
-        $output         = \implode('', $outputLines);
+        $outputLines    = preg_split('/(.*\R)/', $output, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
+        $outputLines[0] = preg_replace('#^\-\-\- .*#', '--- /' . $this->fileFrom, $outputLines[0], 1);
+        $outputLines[1] = preg_replace('#^\+\+\+ .*#', '+++ /' . $this->fileFrom, $outputLines[1], 1);
+        $output         = implode('', $outputLines);
 
         $this->assertSame($diff, $output);
     }
@@ -224,16 +226,17 @@ private function doIntegrationTestGitApply(string $diff, string $from, string $t
 
         $diff = self::setDiffFileHeader($diff, $this->fileFrom);
 
-        $this->assertNotFalse(\file_put_contents($this->fileFrom, $from));
-        $this->assertNotFalse(\file_put_contents($this->filePatch, $diff));
+        $this->assertNotFalse(file_put_contents($this->fileFrom, $from));
+        $this->assertNotFalse(file_put_contents($this->filePatch, $diff));
 
-        $p = new Process(\sprintf(
-            'git --git-dir %s apply --check -v --unsafe-paths --ignore-whitespace %s',
-            \escapeshellarg($this->dir),
-            \escapeshellarg($this->filePatch)
-        ));
-
-        $p->run();
+        $p = Process::fromShellCommandline('git --git-dir $dir apply --check -v --unsafe-paths --ignore-whitespace $patch');
+        $p->run(
+            null,
+            [
+                'dir'   => $this->dir,
+                'patch' => $this->filePatch,
+            ]
+        );
 
         $this->assertProcessSuccessful($p);
     }
@@ -245,24 +248,24 @@ private function doIntegrationTestPatch(string $diff, string $from, string $to):
 
         $diff = self::setDiffFileHeader($diff, $this->fileFrom);
 
-        $this->assertNotFalse(\file_put_contents($this->fileFrom, $from));
-        $this->assertNotFalse(\file_put_contents($this->filePatch, $diff));
+        $this->assertNotFalse(file_put_contents($this->fileFrom, $from));
+        $this->assertNotFalse(file_put_contents($this->filePatch, $diff));
 
-        $command = \sprintf(
-            'patch -u --verbose --posix %s < %s',
-            \escapeshellarg($this->fileFrom),
-            \escapeshellarg($this->filePatch)
+        $p = Process::fromShellCommandline('patch -u --verbose --posix $from < $patch');
+        $p->run(
+            null,
+            [
+                'from'  => $this->fileFrom,
+                'patch' => $this->filePatch,
+            ]
         );
 
-        $p = new Process($command);
-        $p->run();
-
         $this->assertProcessSuccessful($p);
 
         $this->assertStringEqualsFile(
             $this->fileFrom,
             $to,
-            \sprintf('Patch command "%s".', $command)
+            sprintf('Patch command "%s".', $p->getCommandLine())
         );
     }
 
@@ -270,7 +273,7 @@ private function assertProcessSuccessful(Process $p): void
     {
         $this->assertTrue(
             $p->isSuccessful(),
-            \sprintf(
+            sprintf(
                 "Command exec. was not successful:\n\"%s\"\nOutput:\n\"%s\"\nStdErr:\n\"%s\"\nExit code %d.\n",
                 $p->getCommandLine(),
                 $p->getOutput(),
@@ -282,19 +285,19 @@ private function assertProcessSuccessful(Process $p): void
 
     private function cleanUpTempFiles(): void
     {
-        @\unlink($this->fileFrom . '.orig');
-        @\unlink($this->fileFrom . '.rej');
-        @\unlink($this->fileFrom);
-        @\unlink($this->fileTo);
-        @\unlink($this->filePatch);
+        @unlink($this->fileFrom . '.orig');
+        @unlink($this->fileFrom . '.rej');
+        @unlink($this->fileFrom);
+        @unlink($this->fileTo);
+        @unlink($this->filePatch);
     }
 
     private static function setDiffFileHeader(string $diff, string $file): string
     {
-        $diffLines    = \preg_split('/(.*\R)/', $diff, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
-        $diffLines[0] = \preg_replace('#^\-\-\- .*#', '--- /' . $file, $diffLines[0], 1);
-        $diffLines[1] = \preg_replace('#^\+\+\+ .*#', '+++ /' . $file, $diffLines[1], 1);
+        $diffLines    = preg_split('/(.*\R)/', $diff, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
+        $diffLines[0] = preg_replace('#^\-\-\- .*#', '--- /' . $file, $diffLines[0], 1);
+        $diffLines[1] = preg_replace('#^\+\+\+ .*#', '+++ /' . $file, $diffLines[1], 1);
 
-        return \implode('', $diffLines);
+        return implode('', $diffLines);
     }
 }
diff --git a/tests/Output/Integration/UnifiedDiffOutputBuilderIntegrationTest.php b/tests/Output/Integration/UnifiedDiffOutputBuilderIntegrationTest.php
index 0d96c457..a1bfee6d 100644
--- a/tests/Output/Integration/UnifiedDiffOutputBuilderIntegrationTest.php
+++ b/tests/Output/Integration/UnifiedDiffOutputBuilderIntegrationTest.php
@@ -7,18 +7,30 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
-use PHPUnit\Framework\TestCase;
+use const ARRAY_FILTER_USE_KEY;
+use const PREG_SPLIT_DELIM_CAPTURE;
+use const PREG_SPLIT_NO_EMPTY;
+use function array_filter;
+use function file_put_contents;
+use function implode;
+use function is_string;
+use function preg_replace;
+use function preg_split;
+use function realpath;
+use function sprintf;
+use function strpos;
+use function unlink;
 use Localheinz\Diff\Utils\UnifiedDiffAssertTrait;
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\Process\Process;
 
 /**
- * @covers Localheinz\Diff\Output\UnifiedDiffOutputBuilder
+ * @covers \Localheinz\Diff\Output\UnifiedDiffOutputBuilder
  *
- * @uses Localheinz\Diff\Differ
- * @uses Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
+ * @uses \Localheinz\Diff\Differ
+ * @uses \Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
  *
  * @requires OS Linux
  */
@@ -34,7 +46,7 @@ final class UnifiedDiffOutputBuilderIntegrationTest extends TestCase
 
     protected function setUp(): void
     {
-        $this->dir       = \realpath(__DIR__ . '/../../fixtures/out/') . '/';
+        $this->dir       = realpath(__DIR__ . '/../../fixtures/out/') . '/';
         $this->fileFrom  = $this->dir . 'from.txt';
         $this->filePatch = $this->dir . 'patch.txt';
 
@@ -48,10 +60,6 @@ protected function tearDown(): void
 
     /**
      * @dataProvider provideDiffWithLineNumbers
-     *
-     * @param mixed $expected
-     * @param mixed $from
-     * @param mixed $to
      */
     public function testDiffWithLineNumbersPath($expected, $from, $to): void
     {
@@ -60,10 +68,6 @@ public function testDiffWithLineNumbersPath($expected, $from, $to): void
 
     /**
      * @dataProvider provideDiffWithLineNumbers
-     *
-     * @param mixed $expected
-     * @param mixed $from
-     * @param mixed $to
      */
     public function testDiffWithLineNumbersGitApply($expected, $from, $to): void
     {
@@ -72,10 +76,10 @@ public function testDiffWithLineNumbersGitApply($expected, $from, $to): void
 
     public function provideDiffWithLineNumbers()
     {
-        return \array_filter(
+        return array_filter(
             UnifiedDiffOutputBuilderDataProvider::provideDiffWithLineNumbers(),
             static function ($key) {
-                return !\is_string($key) || false === \strpos($key, 'non_patch_compat');
+                return !is_string($key) || false === strpos($key, 'non_patch_compat');
             },
             ARRAY_FILTER_USE_KEY
         );
@@ -88,24 +92,24 @@ private function doIntegrationTestPatch(string $diff, string $from, string $to):
 
         $diff = self::setDiffFileHeader($diff, $this->fileFrom);
 
-        $this->assertNotFalse(\file_put_contents($this->fileFrom, $from));
-        $this->assertNotFalse(\file_put_contents($this->filePatch, $diff));
+        $this->assertNotFalse(file_put_contents($this->fileFrom, $from));
+        $this->assertNotFalse(file_put_contents($this->filePatch, $diff));
 
-        $command = \sprintf(
-            'patch -u --verbose --posix  %s < %s', // --posix
-            \escapeshellarg($this->fileFrom),
-            \escapeshellarg($this->filePatch)
+        $p = Process::fromShellCommandline('patch -u --verbose --posix $from < $patch'); // --posix
+        $p->run(
+            null,
+            [
+                'from'  => $this->fileFrom,
+                'patch' => $this->filePatch,
+            ]
         );
 
-        $p = new Process($command);
-        $p->run();
-
         $this->assertProcessSuccessful($p);
 
         $this->assertStringEqualsFile(
             $this->fileFrom,
             $to,
-            \sprintf('Patch command "%s".', $command)
+            sprintf('Patch command "%s".', $p->getCommandLine())
         );
     }
 
@@ -116,18 +120,18 @@ private function doIntegrationTestGitApply(string $diff, string $from, string $t
 
         $diff = self::setDiffFileHeader($diff, $this->fileFrom);
 
-        $this->assertNotFalse(\file_put_contents($this->fileFrom, $from));
-        $this->assertNotFalse(\file_put_contents($this->filePatch, $diff));
+        $this->assertNotFalse(file_put_contents($this->fileFrom, $from));
+        $this->assertNotFalse(file_put_contents($this->filePatch, $diff));
 
-        $command = \sprintf(
-            'git --git-dir %s apply --check -v --unsafe-paths --ignore-whitespace %s',
-            \escapeshellarg($this->dir),
-            \escapeshellarg($this->filePatch)
+        $p = Process::fromShellCommandline('git --git-dir $dir apply --check -v --unsafe-paths --ignore-whitespace $patch');
+        $p->run(
+            null,
+            [
+                'dir'   => $this->dir,
+                'patch' => $this->filePatch,
+            ]
         );
 
-        $p = new Process($command);
-        $p->run();
-
         $this->assertProcessSuccessful($p);
     }
 
@@ -135,7 +139,7 @@ private function assertProcessSuccessful(Process $p): void
     {
         $this->assertTrue(
             $p->isSuccessful(),
-            \sprintf(
+            sprintf(
                 "Command exec. was not successful:\n\"%s\"\nOutput:\n\"%s\"\nStdErr:\n\"%s\"\nExit code %d.\n",
                 $p->getCommandLine(),
                 $p->getOutput(),
@@ -147,17 +151,17 @@ private function assertProcessSuccessful(Process $p): void
 
     private function cleanUpTempFiles(): void
     {
-        @\unlink($this->fileFrom . '.orig');
-        @\unlink($this->fileFrom);
-        @\unlink($this->filePatch);
+        @unlink($this->fileFrom . '.orig');
+        @unlink($this->fileFrom);
+        @unlink($this->filePatch);
     }
 
     private static function setDiffFileHeader(string $diff, string $file): string
     {
-        $diffLines    = \preg_split('/(.*\R)/', $diff, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
-        $diffLines[0] = \preg_replace('#^\-\-\- .*#', '--- /' . $file, $diffLines[0], 1);
-        $diffLines[1] = \preg_replace('#^\+\+\+ .*#', '+++ /' . $file, $diffLines[1], 1);
+        $diffLines    = preg_split('/(.*\R)/', $diff, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
+        $diffLines[0] = preg_replace('#^\-\-\- .*#', '--- /' . $file, $diffLines[0], 1);
+        $diffLines[1] = preg_replace('#^\+\+\+ .*#', '+++ /' . $file, $diffLines[1], 1);
 
-        return \implode('', $diffLines);
+        return implode('', $diffLines);
     }
 }
diff --git a/tests/Output/StrictUnifiedDiffOutputBuilderDataProvider.php b/tests/Output/StrictUnifiedDiffOutputBuilderDataProvider.php
index 22a359fc..8a3f0abf 100644
--- a/tests/Output/StrictUnifiedDiffOutputBuilderDataProvider.php
+++ b/tests/Output/StrictUnifiedDiffOutputBuilderDataProvider.php
@@ -7,7 +7,6 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
 final class StrictUnifiedDiffOutputBuilderDataProvider
@@ -16,7 +15,7 @@ public static function provideOutputBuildingCases(): array
     {
         return [
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1,3 +1,4 @@
 +b
@@ -39,7 +38,7 @@ public static function provideOutputBuildingCases(): array
                 ],
             ],
             [
-'--- ' . __FILE__ . "\t2017-10-02 17:38:11.586413675 +0100
+                '--- ' . __FILE__ . "\t2017-10-02 17:38:11.586413675 +0100
 +++ output1.txt\t2017-10-03 12:09:43.086719482 +0100
 @@ -1,1 +1,1 @@
 -B
@@ -56,7 +55,7 @@ public static function provideOutputBuildingCases(): array
                 ],
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1 +1 @@
 -B
@@ -77,7 +76,7 @@ public static function provideSample(): array
     {
         return [
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1,6 +1,6 @@
  1
@@ -102,7 +101,7 @@ public static function provideBasicDiffGeneration(): array
     {
         return [
             [
-"--- input.txt
+                "--- input.txt
 +++ output.txt
 @@ -1,2 +1 @@
 -A
@@ -113,7 +112,7 @@ public static function provideBasicDiffGeneration(): array
                 "A\rB\n",
             ],
             [
-"--- input.txt
+                "--- input.txt
 +++ output.txt
 @@ -1 +1 @@
 -
@@ -124,7 +123,7 @@ public static function provideBasicDiffGeneration(): array
                 "\r",
             ],
             [
-"--- input.txt
+                "--- input.txt
 +++ output.txt
 @@ -1 +1 @@
 -\r
@@ -135,7 +134,7 @@ public static function provideBasicDiffGeneration(): array
                 "\n",
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1,3 +1,3 @@
  X
@@ -147,7 +146,7 @@ public static function provideBasicDiffGeneration(): array
                 "X\nA\nB\n",
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1,3 +1,3 @@
  X
@@ -160,7 +159,7 @@ public static function provideBasicDiffGeneration(): array
                 "X\nA\nB\n",
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1,3 +1,3 @@
  A
@@ -173,7 +172,7 @@ public static function provideBasicDiffGeneration(): array
                 "A\nA\nB",
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1 +1 @@
 -A
diff --git a/tests/Output/StrictUnifiedDiffOutputBuilderTest.php b/tests/Output/StrictUnifiedDiffOutputBuilderTest.php
index 2d3391a3..f1aa9de3 100644
--- a/tests/Output/StrictUnifiedDiffOutputBuilderTest.php
+++ b/tests/Output/StrictUnifiedDiffOutputBuilderTest.php
@@ -7,31 +7,31 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
-use PHPUnit\Framework\TestCase;
+use function array_merge;
+use function preg_quote;
+use function sprintf;
+use function substr;
+use function time;
 use Localheinz\Diff\ConfigurationException;
 use Localheinz\Diff\Differ;
 use Localheinz\Diff\Utils\UnifiedDiffAssertTrait;
+use PHPUnit\Framework\TestCase;
+use SplFileInfo;
 
 /**
- * @covers Localheinz\Diff\Output\StrictUnifiedDiffOutputBuilder
+ * @covers \Localheinz\Diff\Output\StrictUnifiedDiffOutputBuilder
  *
- * @uses Localheinz\Diff\Differ
- * @uses Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
- * @uses Localheinz\Diff\ConfigurationException
+ * @uses \Localheinz\Diff\Differ
+ * @uses \Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
+ * @uses \Localheinz\Diff\ConfigurationException
  */
 final class StrictUnifiedDiffOutputBuilderTest extends TestCase
 {
     use UnifiedDiffAssertTrait;
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     * @param array  $options
-     *
      * @dataProvider provideOutputBuildingCases
      */
     public function testOutputBuilding(string $expected, string $from, string $to, array $options): void
@@ -43,11 +43,6 @@ public function testOutputBuilding(string $expected, string $from, string $to, a
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     * @param array  $options
-     *
      * @dataProvider provideSample
      */
     public function testSample(string $expected, string $from, string $to, array $options): void
@@ -83,10 +78,6 @@ public function provideSample(): array
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     *
      * @dataProvider provideBasicDiffGeneration
      */
     public function testBasicDiffGeneration(string $expected, string $from, string $to): void
@@ -106,16 +97,11 @@ public function provideBasicDiffGeneration(): array
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     * @param array  $config
-     *
      * @dataProvider provideConfiguredDiffGeneration
      */
     public function testConfiguredDiffGeneration(string $expected, string $from, string $to, array $config = []): void
     {
-        $diff = $this->getDiffer(\array_merge([
+        $diff = $this->getDiffer(array_merge([
             'fromFile' => 'input.txt',
             'toFile'   => 'output.txt',
         ], $config))->diff($from, $to);
@@ -150,7 +136,7 @@ public function provideConfiguredDiffGeneration(): array
                 "1\n",
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -4 +4 @@
 -X
@@ -163,7 +149,7 @@ public function provideConfiguredDiffGeneration(): array
                 ],
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -3,3 +3,3 @@
  3
@@ -178,7 +164,7 @@ public function provideConfiguredDiffGeneration(): array
                 ],
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1,10 +1,10 @@
  1
@@ -200,7 +186,7 @@ public function provideConfiguredDiffGeneration(): array
                 ],
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1,0 +1,2 @@
 +
@@ -210,7 +196,7 @@ public function provideConfiguredDiffGeneration(): array
                 "\nA\n",
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -1,2 +1,0 @@
 -
@@ -275,7 +261,7 @@ public function testReUseBuilder(): void
 
         $diff = $differ->diff("A\nB\n", "A\nX\n");
         $this->assertSame(
-'--- input.txt
+            '--- input.txt
 +++ output.txt
 @@ -1,2 +1,2 @@
  A
@@ -306,22 +292,19 @@ public function testEmptyDiff(): void
     }
 
     /**
-     * @param array  $options
-     * @param string $message
-     *
      * @dataProvider provideInvalidConfiguration
      */
     public function testInvalidConfiguration(array $options, string $message): void
     {
         $this->expectException(ConfigurationException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote($message, '#')));
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote($message, '#')));
 
         new StrictUnifiedDiffOutputBuilder($options);
     }
 
     public function provideInvalidConfiguration(): array
     {
-        $time = \time();
+        $time = time();
 
         return [
             [
@@ -341,7 +324,7 @@ public function provideInvalidConfiguration(): array
                 'Option "commonLineThreshold" must be an int > 0, got "integer#0".',
             ],
             [
-                ['fromFile' => new \SplFileInfo(__FILE__)],
+                ['fromFile' => new SplFileInfo(__FILE__)],
                 'Option "fromFile" must be a string, got "SplFileInfo".',
             ],
             [
@@ -371,11 +354,6 @@ public function provideInvalidConfiguration(): array
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     * @param int    $threshold
-     *
      * @dataProvider provideCommonLineThresholdCases
      */
     public function testCommonLineThreshold(string $expected, string $from, string $to, int $threshold): void
@@ -395,7 +373,7 @@ public function provideCommonLineThresholdCases(): array
     {
         return [
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -2,3 +2,3 @@
 -X
@@ -412,7 +390,7 @@ public function provideCommonLineThresholdCases(): array
                 2,
             ],
             [
-'--- input.txt
+                '--- input.txt
 +++ output.txt
 @@ -2 +2 @@
 -X
@@ -429,12 +407,6 @@ public function provideCommonLineThresholdCases(): array
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     * @param int    $contextLines
-     * @param int    $commonLineThreshold
-     *
      * @dataProvider provideContextLineConfigurationCases
      */
     public function testContextLineConfiguration(string $expected, string $from, string $to, int $contextLines, int $commonLineThreshold = 6): void
@@ -478,7 +450,7 @@ public function provideContextLineConfigurationCases(): array
                 "A\nB\nX",
                 "A\nB\nY",
                 1,
-],
+            ],
             'EOF 2' => [
                 "--- input.txt\n+++ output.txt\n@@ -1,3 +1,3 @@
  A
@@ -556,25 +528,25 @@ public function provideContextLineConfigurationCases(): array
             'M no linebreak EOF .1' => [
                 "--- input.txt\n+++ output.txt\n@@ -1,14 +1,14 @@\n A\n B\n C\n D\n E\n F\n-X\n+Y\n G\n H\n I\n J\n K\n L\n-M\n+M\n\\ No newline at end of file\n",
                 $from,
-                \substr($to, 0, -1),
+                substr($to, 0, -1),
                 7,
             ],
             'M no linebreak EOF .2' => [
                 "--- input.txt\n+++ output.txt\n@@ -1,14 +1,14 @@\n A\n B\n C\n D\n E\n F\n-X\n+Y\n G\n H\n I\n J\n K\n L\n-M\n\\ No newline at end of file\n+M\n",
-                \substr($from, 0, -1),
+                substr($from, 0, -1),
                 $to,
                 7,
             ],
             'M no linebreak EOF .3' => [
                 "--- input.txt\n+++ output.txt\n@@ -1,14 +1,14 @@\n A\n B\n C\n D\n E\n F\n-X\n+Y\n G\n H\n I\n J\n K\n L\n M\n",
-                \substr($from, 0, -1),
-                \substr($to, 0, -1),
+                substr($from, 0, -1),
+                substr($to, 0, -1),
                 7,
             ],
             'M no linebreak EOF .4' => [
                 "--- input.txt\n+++ output.txt\n@@ -1,14 +1,14 @@\n A\n B\n C\n D\n E\n F\n-X\n+Y\n G\n H\n I\n J\n K\n L\n M\n\\ No newline at end of file\n",
-                \substr($from, 0, -1),
-                \substr($to, 0, -1),
+                substr($from, 0, -1),
+                substr($to, 0, -1),
                 10000,
                 10000,
             ],
@@ -674,10 +646,6 @@ public function provideContextLineConfigurationCases(): array
 
     /**
      * Returns a new instance of a Differ with a new instance of the class (DiffOutputBuilderInterface) under test.
-     *
-     * @param array $options
-     *
-     * @return Differ
      */
     private function getDiffer(array $options = []): Differ
     {
diff --git a/tests/Output/UnifiedDiffOutputBuilderDataProvider.php b/tests/Output/UnifiedDiffOutputBuilderDataProvider.php
index af6748be..bea832cc 100644
--- a/tests/Output/UnifiedDiffOutputBuilderDataProvider.php
+++ b/tests/Output/UnifiedDiffOutputBuilderDataProvider.php
@@ -7,7 +7,6 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
 final class UnifiedDiffOutputBuilderDataProvider
@@ -16,7 +15,7 @@ public static function provideDiffWithLineNumbers(): array
     {
         return [
             'diff line 1 non_patch_compat' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -1 +1 @@
 -AA
@@ -26,7 +25,7 @@ public static function provideDiffWithLineNumbers(): array
                 'BA',
             ],
             'diff line +1 non_patch_compat' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -1 +1,2 @@
 -AZ
@@ -37,7 +36,7 @@ public static function provideDiffWithLineNumbers(): array
                 "\nB",
             ],
             'diff line -1 non_patch_compat' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -1,2 +1 @@
 -
@@ -48,7 +47,7 @@ public static function provideDiffWithLineNumbers(): array
                 'B',
             ],
             'II non_patch_compat' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -1,4 +1,2 @@
 -
@@ -60,7 +59,7 @@ public static function provideDiffWithLineNumbers(): array
                 "A\n1",
             ],
             'diff last line II - no trailing linebreak non_patch_compat' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -5,4 +5,4 @@
  ' . '
@@ -82,15 +81,15 @@ public static function provideDiffWithLineNumbers(): array
                 "<?php\r\n",
                 "<?php\n",
             ],
-        'same non_patch_compat' => [
-'--- Original
+            'same non_patch_compat' => [
+                '--- Original
 +++ New
 ',
                 "AT\n",
                 "AT\n",
             ],
             [
-'--- Original
+                '--- Original
 +++ New
 @@ -1,4 +1,4 @@
 -b
@@ -103,7 +102,7 @@ public static function provideDiffWithLineNumbers(): array
                 "a\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n",
             ],
             'diff line @1' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -1,2 +1,2 @@
  ' . '
@@ -114,7 +113,7 @@ public static function provideDiffWithLineNumbers(): array
                 "\nB\n",
             ],
             'same multiple lines' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -1,4 +1,4 @@
  ' . '
@@ -127,7 +126,7 @@ public static function provideDiffWithLineNumbers(): array
                 "\n\nB\nC213",
             ],
             'diff last line I' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -5,4 +5,4 @@
  ' . '
@@ -140,7 +139,7 @@ public static function provideDiffWithLineNumbers(): array
                 "A\n\n\n\n\n\n\nB\n",
             ],
             'diff line middle' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -5,7 +5,7 @@
  ' . '
@@ -156,7 +155,7 @@ public static function provideDiffWithLineNumbers(): array
                 "A\n\n\n\n\n\n\nZ\n\n\n\n\n\n\nAY",
             ],
             'diff last line III' => [
-'--- Original
+                '--- Original
 +++ New
 @@ -12,4 +12,4 @@
  ' . '
@@ -169,7 +168,7 @@ public static function provideDiffWithLineNumbers(): array
                 "A\n\n\n\n\n\n\nA\n\n\n\n\n\n\nB\n",
             ],
             [
-'--- Original
+                '--- Original
 +++ New
 @@ -1,8 +1,8 @@
  A
@@ -187,7 +186,7 @@ public static function provideDiffWithLineNumbers(): array
                 "A\nB1\nD\nE\nEE\nF\nG1\nH",
             ],
             [
-'--- Original
+                '--- Original
 +++ New
 @@ -1,4 +1,5 @@
  Z
@@ -203,7 +202,7 @@ public static function provideDiffWithLineNumbers(): array
 +x
  j
 ',
-'Z
+                'Z
 a
 b
 c
@@ -215,7 +214,7 @@ public static function provideDiffWithLineNumbers(): array
 i
 j
 ',
-'Z
+                'Z
 
 a
 b
@@ -230,7 +229,7 @@ public static function provideDiffWithLineNumbers(): array
 ',
             ],
             [
-'--- Original
+                '--- Original
 +++ New
 @@ -1,7 +1,5 @@
 -
@@ -247,7 +246,7 @@ public static function provideDiffWithLineNumbers(): array
                 "b\nA\nY\n\nA\n",
             ],
             [
-<<<EOF
+                <<<EOF
 --- Original
 +++ New
 @@ -1,7 +1,5 @@
@@ -273,7 +272,7 @@ public static function provideDiffWithLineNumbers(): array
                 "a\np\nc\nd\ne\nf\ng\nh\ni\nw\nk\n",
             ],
             [
-'--- Original
+                '--- Original
 +++ New
 @@ -8,7 +8,7 @@
  ' . '
@@ -289,7 +288,7 @@ public static function provideDiffWithLineNumbers(): array
                 "E\n\n\n\n\nB\n\n\n\n\nC\n\n\n\n\n\n\n\n\nD1",
             ],
             [
-'--- Original
+                '--- Original
 +++ New
 @@ -5,7 +5,7 @@
  ' . '
@@ -347,7 +346,7 @@ public static function provideDiffWithLineNumbers(): array
                 "\n\n\n\n\n\n\nU\n\n\n\n\n\n\nV\n\n\n\n\n\n\nW\n\n\n\n\n\n\nX\n\n\n\n\n\n\nY\n\n\n\n\n\n\nZ\n",
             ],
             [
-<<<EOF
+                <<<EOF
 --- Original
 +++ New
 @@ -1,5 +1,5 @@
@@ -371,7 +370,7 @@ public static function provideDiffWithLineNumbers(): array
                 "a\np\nc\nd\ne\nf\ng\nh\ni\nw\nk\n",
             ],
             [
-<<<EOF
+                <<<EOF
 --- Original
 +++ New
 @@ -1,4 +1,4 @@
diff --git a/tests/Output/UnifiedDiffOutputBuilderTest.php b/tests/Output/UnifiedDiffOutputBuilderTest.php
index 74ef17ad..a0ac6e6e 100644
--- a/tests/Output/UnifiedDiffOutputBuilderTest.php
+++ b/tests/Output/UnifiedDiffOutputBuilderTest.php
@@ -7,27 +7,21 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Output;
 
-use PHPUnit\Framework\TestCase;
 use Localheinz\Diff\Differ;
+use PHPUnit\Framework\TestCase;
 
 /**
- * @covers Localheinz\Diff\Output\UnifiedDiffOutputBuilder
+ * @covers \Localheinz\Diff\Output\UnifiedDiffOutputBuilder
  *
- * @uses Localheinz\Diff\Differ
- * @uses Localheinz\Diff\Output\AbstractChunkOutputBuilder
- * @uses Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
+ * @uses \Localheinz\Diff\Differ
+ * @uses \Localheinz\Diff\Output\AbstractChunkOutputBuilder
+ * @uses \Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
  */
 final class UnifiedDiffOutputBuilderTest extends TestCase
 {
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     * @param string $header
-     *
      * @dataProvider headerProvider
      */
     public function testCustomHeaderCanBeUsed(string $expected, string $from, string $to, string $header): void
@@ -71,13 +65,9 @@ public function headerProvider(): array
     }
 
     /**
-     * @param string $expected
-     * @param string $from
-     * @param string $to
-     *
      * @dataProvider provideDiffWithLineNumbers
      */
-    public function testDiffWithLineNumbers($expected, $from, $to): void
+    public function testDiffWithLineNumbers(string $expected, string $from, string $to): void
     {
         $differ = new Differ(new UnifiedDiffOutputBuilder("--- Original\n+++ New\n", true));
         $this->assertSame($expected, $differ->diff($from, $to));
@@ -87,4 +77,27 @@ public function provideDiffWithLineNumbers(): array
     {
         return UnifiedDiffOutputBuilderDataProvider::provideDiffWithLineNumbers();
     }
+
+    /**
+     * @dataProvider provideStringsThatAreTheSame
+     */
+    public function testEmptyDiffProducesEmptyOutput(string $from, string $to): void
+    {
+        $differ = new Differ(new UnifiedDiffOutputBuilder('', false));
+
+        $output = $differ->diff($from, $to);
+
+        $this->assertEmpty($output);
+    }
+
+    public function provideStringsThatAreTheSame(): array
+    {
+        return [
+            ['', ''],
+            ['a', 'a'],
+            ['these strings are the same', 'these strings are the same'],
+            ["\n", "\n"],
+            ["multi-line strings\nare the same", "multi-line strings\nare the same"],
+        ];
+    }
 }
diff --git a/tests/ParserTest.php b/tests/ParserTest.php
index 3999c0fc..0da5ef77 100644
--- a/tests/ParserTest.php
+++ b/tests/ParserTest.php
@@ -7,18 +7,18 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
-use PHPUnit\Framework\TestCase;
+use function unserialize;
 use Localheinz\Diff\Utils\FileUtils;
+use PHPUnit\Framework\TestCase;
 
 /**
- * @covers Localheinz\Diff\Parser
+ * @covers \Localheinz\Diff\Parser
  *
- * @uses Localheinz\Diff\Chunk
- * @uses Localheinz\Diff\Diff
- * @uses Localheinz\Diff\Line
+ * @uses \Localheinz\Diff\Chunk
+ * @uses \Localheinz\Diff\Diff
+ * @uses \Localheinz\Diff\Line
  */
 final class ParserTest extends TestCase
 {
@@ -146,8 +146,7 @@ public function testParseDiffForMulitpleFiles(): void
     }
 
     /**
-     * @param string $diff
-     * @param Diff[] $expected
+     * @psalm-param list<Diff> $expected
      *
      * @dataProvider diffProvider
      */
@@ -163,7 +162,7 @@ public function diffProvider(): array
         return [
             [
                 "--- old.txt	2014-11-04 08:51:02.661868729 +0300\n+++ new.txt	2014-11-04 08:51:02.665868730 +0300\n@@ -1,3 +1,4 @@\n+2222111\n 1111111\n 1111111\n 1111111\n@@ -5,10 +6,8 @@\n 1111111\n 1111111\n 1111111\n +1121211\n 1111111\n -1111111\n -1111111\n -2222222\n 2222222\n 2222222\n 2222222\n@@ -17,5 +16,6 @@\n 2222222\n 2222222\n 2222222\n +2122212\n 2222222\n 2222222\n",
-                \unserialize(FileUtils::getFileContent(__DIR__ . '/fixtures/serialized_diff.bin')),
+                unserialize(FileUtils::getFileContent(__DIR__ . '/fixtures/serialized_diff.bin')),
             ],
         ];
     }
diff --git a/tests/TimeEfficientImplementationTest.php b/tests/TimeEfficientImplementationTest.php
index 5eb36e15..add61c8c 100644
--- a/tests/TimeEfficientImplementationTest.php
+++ b/tests/TimeEfficientImplementationTest.php
@@ -7,11 +7,10 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff;
 
 /**
- * @covers Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
+ * @covers \Localheinz\Diff\TimeEfficientLongestCommonSubsequenceCalculator
  */
 final class TimeEfficientImplementationTest extends LongestCommonSubsequenceTest
 {
diff --git a/tests/Utils/FileUtils.php b/tests/Utils/FileUtils.php
index 335171f1..ca3a6b8b 100644
--- a/tests/Utils/FileUtils.php
+++ b/tests/Utils/FileUtils.php
@@ -7,19 +7,23 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Utils;
 
+use function error_get_last;
+use function file_get_contents;
+use function sprintf;
+use RuntimeException;
+
 final class FileUtils
 {
     public static function getFileContent(string $file): string
     {
-        $content = @\file_get_contents($file);
+        $content = @file_get_contents($file);
 
         if (false === $content) {
-            $error = \error_get_last();
+            $error = error_get_last();
 
-            throw new \RuntimeException(\sprintf(
+            throw new RuntimeException(sprintf(
                 'Failed to read content of file "%s".%s',
                 $file,
                 $error ? ' ' . $error['message'] : ''
diff --git a/tests/Utils/UnifiedDiffAssertTrait.php b/tests/Utils/UnifiedDiffAssertTrait.php
index 4518ec80..b36d7a08 100644
--- a/tests/Utils/UnifiedDiffAssertTrait.php
+++ b/tests/Utils/UnifiedDiffAssertTrait.php
@@ -7,15 +7,24 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Utils;
 
+use const PREG_SPLIT_DELIM_CAPTURE;
+use const PREG_SPLIT_NO_EMPTY;
+use function count;
+use function preg_match;
+use function preg_split;
+use function sprintf;
+use function strlen;
+use function strpos;
+use function substr;
+use RuntimeException;
+use UnexpectedValueException;
+
 trait UnifiedDiffAssertTrait
 {
     /**
-     * @param string $diff
-     *
-     * @throws \UnexpectedValueException
+     * @throws UnexpectedValueException
      */
     public function assertValidUnifiedDiffFormat(string $diff): void
     {
@@ -26,14 +35,14 @@ public function assertValidUnifiedDiffFormat(string $diff): void
         }
 
         // test diff ends with a line break
-        $last = \substr($diff, -1);
+        $last = substr($diff, -1);
 
         if ("\n" !== $last && "\r" !== $last) {
-            throw new \UnexpectedValueException(\sprintf('Expected diff to end with a line break, got "%s".', $last));
+            throw new UnexpectedValueException(sprintf('Expected diff to end with a line break, got "%s".', $last));
         }
 
-        $lines            = \preg_split('/(.*\R)/', $diff, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
-        $lineCount        = \count($lines);
+        $lines            = preg_split('/(.*\R)/', $diff, -1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
+        $lineCount        = count($lines);
         $lineNumber       = $diffLineFromNumber       = $diffLineToNumber       = 1;
         $fromStart        = $fromTillOffset        = $toStart        = $toTillOffset        = -1;
         $expectHunkHeader = true;
@@ -43,9 +52,9 @@ public function assertValidUnifiedDiffFormat(string $diff): void
             $this->unifiedDiffAssertLinePrefix($lines[0], 'Line 1.');
             $this->unifiedDiffAssertLinePrefix($lines[1], 'Line 2.');
 
-            if ('---' === \substr($lines[0], 0, 3)) {
-                if ('+++' !== \substr($lines[1], 0, 3)) {
-                    throw new \UnexpectedValueException(\sprintf("Line 1 indicates a header, so line 2 must start with \"+++\".\nLine 1: \"%s\"\nLine 2: \"%s\".", $lines[0], $lines[1]));
+            if ('---' === substr($lines[0], 0, 3)) {
+                if ('+++' !== substr($lines[1], 0, 3)) {
+                    throw new UnexpectedValueException(sprintf("Line 1 indicates a header, so line 2 must start with \"+++\".\nLine 1: \"%s\"\nLine 2: \"%s\".", $lines[0], $lines[1]));
                 }
 
                 $this->unifiedDiffAssertHeaderLine($lines[0], '--- ', 'Line 1.');
@@ -61,33 +70,33 @@ public function assertValidUnifiedDiffFormat(string $diff): void
         // assert format of lines, get all hunks, test the line numbers
         for (; $lineNumber <= $lineCount; ++$lineNumber) {
             if ($diffClosed) {
-                throw new \UnexpectedValueException(\sprintf('Unexpected line as 2 "No newline" markers have found, ". Line %d.', $lineNumber));
+                throw new UnexpectedValueException(sprintf('Unexpected line as 2 "No newline" markers have found, ". Line %d.', $lineNumber));
             }
 
             $line = $lines[$lineNumber - 1]; // line numbers start by 1, array index at 0
-            $type = $this->unifiedDiffAssertLinePrefix($line, \sprintf('Line %d.', $lineNumber));
+            $type = $this->unifiedDiffAssertLinePrefix($line, sprintf('Line %d.', $lineNumber));
 
             if ($expectHunkHeader && '@' !== $type && '\\' !== $type) {
-                throw new \UnexpectedValueException(\sprintf('Expected hunk start (\'@\'), got "%s". Line %d.', $type, $lineNumber));
+                throw new UnexpectedValueException(sprintf('Expected hunk start (\'@\'), got "%s". Line %d.', $type, $lineNumber));
             }
 
             if ('@' === $type) {
                 if (!$expectHunkHeader) {
-                    throw new \UnexpectedValueException(\sprintf('Unexpected hunk start (\'@\'). Line %d.', $lineNumber));
+                    throw new UnexpectedValueException(sprintf('Unexpected hunk start (\'@\'). Line %d.', $lineNumber));
                 }
 
                 $previousHunkFromEnd = $fromStart + $fromTillOffset;
                 $previousHunkTillEnd = $toStart + $toTillOffset;
 
-                [$fromStart, $fromTillOffset, $toStart, $toTillOffset] = $this->unifiedDiffAssertHunkHeader($line, \sprintf('Line %d.', $lineNumber));
+                [$fromStart, $fromTillOffset, $toStart, $toTillOffset] = $this->unifiedDiffAssertHunkHeader($line, sprintf('Line %d.', $lineNumber));
 
                 // detect overlapping hunks
                 if ($fromStart < $previousHunkFromEnd) {
-                    throw new \UnexpectedValueException(\sprintf('Unexpected new hunk; "from" (\'-\') start overlaps previous hunk. Line %d.', $lineNumber));
+                    throw new UnexpectedValueException(sprintf('Unexpected new hunk; "from" (\'-\') start overlaps previous hunk. Line %d.', $lineNumber));
                 }
 
                 if ($toStart < $previousHunkTillEnd) {
-                    throw new \UnexpectedValueException(\sprintf('Unexpected new hunk; "to" (\'+\') start overlaps previous hunk. Line %d.', $lineNumber));
+                    throw new UnexpectedValueException(sprintf('Unexpected new hunk; "to" (\'+\') start overlaps previous hunk. Line %d.', $lineNumber));
                 }
 
                 /* valid states; hunks touches against each other:
@@ -104,73 +113,69 @@ public function assertValidUnifiedDiffFormat(string $diff): void
 
             if ('-' === $type) {
                 if (isset($endOfLineTypes['-'])) {
-                    throw new \UnexpectedValueException(\sprintf('Not expected from (\'-\'), already closed by "\\ No newline at end of file". Line %d.', $lineNumber));
+                    throw new UnexpectedValueException(sprintf('Not expected from (\'-\'), already closed by "\\ No newline at end of file". Line %d.', $lineNumber));
                 }
 
                 ++$diffLineFromNumber;
             } elseif ('+' === $type) {
                 if (isset($endOfLineTypes['+'])) {
-                    throw new \UnexpectedValueException(\sprintf('Not expected to (\'+\'), already closed by "\\ No newline at end of file". Line %d.', $lineNumber));
+                    throw new UnexpectedValueException(sprintf('Not expected to (\'+\'), already closed by "\\ No newline at end of file". Line %d.', $lineNumber));
                 }
 
                 ++$diffLineToNumber;
             } elseif (' ' === $type) {
                 if (isset($endOfLineTypes['-'])) {
-                    throw new \UnexpectedValueException(\sprintf('Not expected same (\' \'), \'-\' already closed by "\\ No newline at end of file". Line %d.', $lineNumber));
+                    throw new UnexpectedValueException(sprintf('Not expected same (\' \'), \'-\' already closed by "\\ No newline at end of file". Line %d.', $lineNumber));
                 }
 
                 if (isset($endOfLineTypes['+'])) {
-                    throw new \UnexpectedValueException(\sprintf('Not expected same (\' \'), \'+\' already closed by "\\ No newline at end of file". Line %d.', $lineNumber));
+                    throw new UnexpectedValueException(sprintf('Not expected same (\' \'), \'+\' already closed by "\\ No newline at end of file". Line %d.', $lineNumber));
                 }
 
                 ++$diffLineFromNumber;
                 ++$diffLineToNumber;
             } elseif ('\\' === $type) {
                 if (!isset($lines[$lineNumber - 2])) {
-                    throw new \UnexpectedValueException(\sprintf('Unexpected "\\ No newline at end of file", it must be preceded by \'+\' or \'-\' line. Line %d.', $lineNumber));
+                    throw new UnexpectedValueException(sprintf('Unexpected "\\ No newline at end of file", it must be preceded by \'+\' or \'-\' line. Line %d.', $lineNumber));
                 }
 
-                $previousType = $this->unifiedDiffAssertLinePrefix($lines[$lineNumber - 2], \sprintf('Preceding line of "\\ No newline at end of file" of unexpected format. Line %d.', $lineNumber));
+                $previousType = $this->unifiedDiffAssertLinePrefix($lines[$lineNumber - 2], sprintf('Preceding line of "\\ No newline at end of file" of unexpected format. Line %d.', $lineNumber));
 
                 if (isset($endOfLineTypes[$previousType])) {
-                    throw new \UnexpectedValueException(\sprintf('Unexpected "\\ No newline at end of file", "%s" was already closed. Line %d.', $type, $lineNumber));
+                    throw new UnexpectedValueException(sprintf('Unexpected "\\ No newline at end of file", "%s" was already closed. Line %d.', $type, $lineNumber));
                 }
 
                 $endOfLineTypes[$previousType] = true;
-                $diffClosed                    = \count($endOfLineTypes) > 1;
+                $diffClosed                    = count($endOfLineTypes) > 1;
             } else {
                 // internal state error
-                throw new \RuntimeException(\sprintf('Unexpected line type "%s" Line %d.', $type, $lineNumber));
+                throw new RuntimeException(sprintf('Unexpected line type "%s" Line %d.', $type, $lineNumber));
             }
 
             $expectHunkHeader =
                 $diffLineFromNumber === ($fromStart + $fromTillOffset)
-                && $diffLineToNumber === ($toStart + $toTillOffset)
-            ;
+                && $diffLineToNumber === ($toStart + $toTillOffset);
         }
 
         if (
             $diffLineFromNumber !== ($fromStart + $fromTillOffset)
             && $diffLineToNumber !== ($toStart + $toTillOffset)
         ) {
-            throw new \UnexpectedValueException(\sprintf('Unexpected EOF, number of lines in hunk "from" (\'-\')) and "to" (\'+\') mismatched. Line %d.', $lineNumber));
+            throw new UnexpectedValueException(sprintf('Unexpected EOF, number of lines in hunk "from" (\'-\')) and "to" (\'+\') mismatched. Line %d.', $lineNumber));
         }
 
         if ($diffLineFromNumber !== ($fromStart + $fromTillOffset)) {
-            throw new \UnexpectedValueException(\sprintf('Unexpected EOF, number of lines in hunk "from" (\'-\')) mismatched. Line %d.', $lineNumber));
+            throw new UnexpectedValueException(sprintf('Unexpected EOF, number of lines in hunk "from" (\'-\')) mismatched. Line %d.', $lineNumber));
         }
 
         if ($diffLineToNumber !== ($toStart + $toTillOffset)) {
-            throw new \UnexpectedValueException(\sprintf('Unexpected EOF, number of lines in hunk "to" (\'+\')) mismatched. Line %d.', $lineNumber));
+            throw new UnexpectedValueException(sprintf('Unexpected EOF, number of lines in hunk "to" (\'+\')) mismatched. Line %d.', $lineNumber));
         }
 
         $this->addToAssertionCount(1);
     }
 
     /**
-     * @param string $line
-     * @param string $message
-     *
      * @return string '+', '-', '@', ' ' or '\'
      */
     private function unifiedDiffAssertLinePrefix(string $line, string $message): string
@@ -186,49 +191,45 @@ private function unifiedDiffAssertLinePrefix(string $line, string $message): str
             return '\\';
         }
 
-        throw new \UnexpectedValueException(\sprintf('Expected line to start with \'@\', \'-\' or \'+\', got "%s". %s', $line, $message));
+        throw new UnexpectedValueException(sprintf('Expected line to start with \'@\', \'-\' or \'+\', got "%s". %s', $line, $message));
     }
 
     private function unifiedDiffAssertStrLength(string $line, int $min, string $message): void
     {
-        $length = \strlen($line);
+        $length = strlen($line);
 
         if ($length < $min) {
-            throw new \UnexpectedValueException(\sprintf('Expected string length of minimal %d, got %d. %s', $min, $length, $message));
+            throw new UnexpectedValueException(sprintf('Expected string length of minimal %d, got %d. %s', $min, $length, $message));
         }
     }
 
     /**
-     * Assert valid unified diff header line
+     * Assert valid unified diff header line.
      *
      * Samples:
      * - "+++ from1.txt\t2017-08-24 19:51:29.383985722 +0200"
      * - "+++ from1.txt"
-     *
-     * @param string $line
-     * @param string $start
-     * @param string $message
      */
     private function unifiedDiffAssertHeaderLine(string $line, string $start, string $message): void
     {
-        if (0 !== \strpos($line, $start)) {
-            throw new \UnexpectedValueException(\sprintf('Expected header line to start with "%s", got "%s". %s', $start . ' ', $line, $message));
+        if (0 !== strpos($line, $start)) {
+            throw new UnexpectedValueException(sprintf('Expected header line to start with "%s", got "%s". %s', $start . ' ', $line, $message));
         }
 
         // sample "+++ from1.txt\t2017-08-24 19:51:29.383985722 +0200\n"
-        $match = \preg_match(
+        $match = preg_match(
             "/^([^\t]*)(?:[\t]([\\S].*[\\S]))?\n$/",
-            \substr($line, 4), // 4 === string length of "+++ " / "--- "
+            substr($line, 4), // 4 === string length of "+++ " / "--- "
             $matches
         );
 
         if (1 !== $match) {
-            throw new \UnexpectedValueException(\sprintf('Header line does not match expected pattern, got "%s". %s', $line, $message));
+            throw new UnexpectedValueException(sprintf('Header line does not match expected pattern, got "%s". %s', $line, $message));
         }
 
         // $file = $matches[1];
 
-        if (\count($matches) > 2) {
+        if (count($matches) > 2) {
             $this->unifiedDiffAssertHeaderDate($matches[2], $message);
         }
     }
@@ -236,30 +237,27 @@ private function unifiedDiffAssertHeaderLine(string $line, string $start, string
     private function unifiedDiffAssertHeaderDate(string $date, string $message): void
     {
         // sample "2017-08-24 19:51:29.383985722 +0200"
-        $match = \preg_match(
+        $match = preg_match(
             '/^([\d]{4})-([01]?[\d])-([0123]?[\d])(:? [\d]{1,2}:[\d]{1,2}(?::[\d]{1,2}(:?\.[\d]+)?)?(?: ([\+\-][\d]{4}))?)?$/',
             $date,
             $matches
         );
 
-        if (1 !== $match || ($matchesCount = \count($matches)) < 4) {
-            throw new \UnexpectedValueException(\sprintf('Date of header line does not match expected pattern, got "%s". %s', $date, $message));
+        if (1 !== $match || ($matchesCount = count($matches)) < 4) {
+            throw new UnexpectedValueException(sprintf('Date of header line does not match expected pattern, got "%s". %s', $date, $message));
         }
 
         // [$full, $year, $month, $day, $time] = $matches;
     }
 
     /**
-     * @param string $line
-     * @param string $message
-     *
      * @return int[]
      */
     private function unifiedDiffAssertHunkHeader(string $line, string $message): array
     {
-        if (1 !== \preg_match('#^@@ -([\d]+)((?:,[\d]+)?) \+([\d]+)((?:,[\d]+)?) @@\n$#', $line, $matches)) {
-            throw new \UnexpectedValueException(
-                \sprintf(
+        if (1 !== preg_match('#^@@ -([\d]+)((?:,[\d]+)?) \+([\d]+)((?:,[\d]+)?) @@\n$#', $line, $matches)) {
+            throw new UnexpectedValueException(
+                sprintf(
                     'Hunk header line does not match expected pattern, got "%s". %s',
                     $line,
                     $message
@@ -269,9 +267,9 @@ private function unifiedDiffAssertHunkHeader(string $line, string $message): arr
 
         return [
             (int) $matches[1],
-            empty($matches[2]) ? 1 : (int) \substr($matches[2], 1),
+            empty($matches[2]) ? 1 : (int) substr($matches[2], 1),
             (int) $matches[3],
-            empty($matches[4]) ? 1 : (int) \substr($matches[4], 1),
+            empty($matches[4]) ? 1 : (int) substr($matches[4], 1),
         ];
     }
 }
diff --git a/tests/Utils/UnifiedDiffAssertTraitIntegrationTest.php b/tests/Utils/UnifiedDiffAssertTraitIntegrationTest.php
index 19d7e11c..3fdd7e2e 100644
--- a/tests/Utils/UnifiedDiffAssertTraitIntegrationTest.php
+++ b/tests/Utils/UnifiedDiffAssertTraitIntegrationTest.php
@@ -7,10 +7,18 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Utils;
 
+use function file_exists;
+use function realpath;
+use function sprintf;
+use function strlen;
+use function substr;
+use function unlink;
 use PHPUnit\Framework\TestCase;
+use RecursiveDirectoryIterator;
+use RecursiveIteratorIterator;
+use SplFileInfo;
 use Symfony\Component\Process\Process;
 
 /**
@@ -37,23 +45,20 @@ protected function tearDown(): void
     }
 
     /**
-     * @param string $fileFrom
-     * @param string $fileTo
-     *
      * @dataProvider provideFilePairsCases
      */
     public function testValidPatches(string $fileFrom, string $fileTo): void
     {
-        $command = \sprintf(
-            'diff -u %s %s > %s',
-            \escapeshellarg(\realpath($fileFrom)),
-            \escapeshellarg(\realpath($fileTo)),
-            \escapeshellarg($this->filePatch)
+        $p = Process::fromShellCommandline('diff -u $from $to > $patch');
+        $p->run(
+            null,
+            [
+                'from'  => realpath($fileFrom),
+                'to'    => realpath($fileTo),
+                'patch' => $this->filePatch,
+            ]
         );
 
-        $p = new Process($command);
-        $p->run();
-
         $exitCode = $p->getExitCode();
 
         if (0 === $exitCode) {
@@ -66,9 +71,9 @@ public function testValidPatches(string $fileFrom, string $fileTo): void
         $this->assertSame(
             1, // means `diff` found a diff between the files we gave it
             $exitCode,
-            \sprintf(
+            sprintf(
                 "Command exec. was not successful:\n\"%s\"\nOutput:\n\"%s\"\nStdErr:\n\"%s\"\nExit code %d.\n",
-                $command,
+                $p->getCommandLine(),
                 $p->getOutput(),
                 $p->getErrorOutput(),
                 $p->getExitCode()
@@ -86,36 +91,36 @@ public function provideFilePairsCases(): array
         $cases = [];
 
         // created cases based on dedicated fixtures
-        $dir       = \realpath(__DIR__ . '/../fixtures/UnifiedDiffAssertTraitIntegrationTest');
-        $dirLength = \strlen($dir);
+        $dir       = realpath(__DIR__ . '/../fixtures/UnifiedDiffAssertTraitIntegrationTest');
+        $dirLength = strlen($dir);
 
         for ($i = 1;; ++$i) {
-            $fromFile = \sprintf('%s/%d_a.txt', $dir, $i);
-            $toFile   = \sprintf('%s/%d_b.txt', $dir, $i);
+            $fromFile = sprintf('%s/%d_a.txt', $dir, $i);
+            $toFile   = sprintf('%s/%d_b.txt', $dir, $i);
 
-            if (!\file_exists($fromFile)) {
+            if (!file_exists($fromFile)) {
                 break;
             }
 
             $this->assertFileExists($toFile);
-            $cases[\sprintf("Diff file:\n\"%s\"\nvs.\n\"%s\"\n", \substr(\realpath($fromFile), $dirLength), \substr(\realpath($toFile), $dirLength))] = [$fromFile, $toFile];
+            $cases[sprintf("Diff file:\n\"%s\"\nvs.\n\"%s\"\n", substr(realpath($fromFile), $dirLength), substr(realpath($toFile), $dirLength))] = [$fromFile, $toFile];
         }
 
         // create cases based on PHP files within the vendor directory for integration testing
-        $dir       = \realpath(__DIR__ . '/../../vendor');
-        $dirLength = \strlen($dir);
+        $dir       = realpath(__DIR__ . '/../../vendor');
+        $dirLength = strlen($dir);
 
-        $fileIterator = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($dir, \RecursiveDirectoryIterator::SKIP_DOTS));
+        $fileIterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($dir, RecursiveDirectoryIterator::SKIP_DOTS));
         $fromFile     = __FILE__;
 
-        /** @var \SplFileInfo $file */
+        /** @var SplFileInfo $file */
         foreach ($fileIterator as $file) {
             if ('php' !== $file->getExtension()) {
                 continue;
             }
 
             $toFile                                                                                                                                   = $file->getPathname();
-            $cases[\sprintf("Diff file:\n\"%s\"\nvs.\n\"%s\"\n", \substr(\realpath($fromFile), $dirLength), \substr(\realpath($toFile), $dirLength))] = [$fromFile, $toFile];
+            $cases[sprintf("Diff file:\n\"%s\"\nvs.\n\"%s\"\n", substr(realpath($fromFile), $dirLength), substr(realpath($toFile), $dirLength))]      = [$fromFile, $toFile];
             $fromFile                                                                                                                                 = $toFile;
         }
 
@@ -124,6 +129,6 @@ public function provideFilePairsCases(): array
 
     private function cleanUpTempFiles(): void
     {
-        @\unlink($this->filePatch);
+        @unlink($this->filePatch);
     }
 }
diff --git a/tests/Utils/UnifiedDiffAssertTraitTest.php b/tests/Utils/UnifiedDiffAssertTraitTest.php
index 5c7d0aef..943d6fde 100644
--- a/tests/Utils/UnifiedDiffAssertTraitTest.php
+++ b/tests/Utils/UnifiedDiffAssertTraitTest.php
@@ -7,21 +7,21 @@
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
-
 namespace Localheinz\Diff\Utils;
 
+use function preg_quote;
+use function sprintf;
 use PHPUnit\Framework\TestCase;
+use UnexpectedValueException;
 
 /**
- * @covers Localheinz\Diff\Utils\UnifiedDiffAssertTrait
+ * @covers \Localheinz\Diff\Utils\UnifiedDiffAssertTrait
  */
 final class UnifiedDiffAssertTraitTest extends TestCase
 {
     use UnifiedDiffAssertTrait;
 
     /**
-     * @param string $diff
-     *
      * @dataProvider provideValidCases
      */
     public function testValidCases(string $diff): void
@@ -33,7 +33,7 @@ public function provideValidCases(): array
     {
         return [
             [
-'--- Original
+                '--- Original
 +++ New
 @@ -8 +8 @@
 -Z
@@ -41,7 +41,7 @@ public function provideValidCases(): array
 ',
             ],
             [
-'--- Original
+                '--- Original
 +++ New
 @@ -8 +8 @@
 -Z
@@ -59,43 +59,43 @@ public function provideValidCases(): array
 
     public function testNoLinebreakEnd(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Expected diff to end with a line break, got "C".', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Expected diff to end with a line break, got "C".', '#')));
 
         $this->assertValidUnifiedDiffFormat("A\nB\nC");
     }
 
     public function testInvalidStartWithoutHeader(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote("Expected line to start with '@', '-' or '+', got \"A\n\". Line 1.", '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote("Expected line to start with '@', '-' or '+', got \"A\n\". Line 1.", '#')));
 
         $this->assertValidUnifiedDiffFormat("A\n");
     }
 
     public function testInvalidStartHeader1(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote("Line 1 indicates a header, so line 2 must start with \"+++\".\nLine 1: \"--- A\n\"\nLine 2: \"+ 1\n\".", '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote("Line 1 indicates a header, so line 2 must start with \"+++\".\nLine 1: \"--- A\n\"\nLine 2: \"+ 1\n\".", '#')));
 
         $this->assertValidUnifiedDiffFormat("--- A\n+ 1\n");
     }
 
     public function testInvalidStartHeader2(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote("Header line does not match expected pattern, got \"+++ file	X\n\". Line 2.", '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote("Header line does not match expected pattern, got \"+++ file	X\n\". Line 2.", '#')));
 
         $this->assertValidUnifiedDiffFormat("--- A\n+++ file\tX\n");
     }
 
     public function testInvalidStartHeader3(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Date of header line does not match expected pattern, got "[invalid date]". Line 1.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Date of header line does not match expected pattern, got "[invalid date]". Line 1.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-"--- Original\t[invalid date]
+            "--- Original\t[invalid date]
 +++ New
 @@ -1,2 +1,2 @@
 -A
@@ -107,11 +107,11 @@ public function testInvalidStartHeader3(): void
 
     public function testInvalidStartHeader4(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote("Expected header line to start with \"+++  \", got \"+++INVALID\n\". Line 2.", '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote("Expected header line to start with \"+++  \", got \"+++INVALID\n\". Line 2.", '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++INVALID
 @@ -1,2 +1,2 @@
 -A
@@ -123,11 +123,11 @@ public function testInvalidStartHeader4(): void
 
     public function testInvalidLine1(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote("Expected line to start with '@', '-' or '+', got \"1\n\". Line 5.", '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote("Expected line to start with '@', '-' or '+', got \"1\n\". Line 5.", '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8 +8 @@
 -Z
@@ -139,11 +139,11 @@ public function testInvalidLine1(): void
 
     public function testInvalidLine2(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Expected string length of minimal 2, got 1. Line 4.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Expected string length of minimal 2, got 1. Line 4.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8 +8 @@
 
@@ -154,11 +154,11 @@ public function testInvalidLine2(): void
 
     public function testHunkInvalidFormat(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote("Hunk header line does not match expected pattern, got \"@@ INVALID -1,1 +1,1 @@\n\". Line 3.", '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote("Hunk header line does not match expected pattern, got \"@@ INVALID -1,1 +1,1 @@\n\". Line 3.", '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ INVALID -1,1 +1,1 @@
 -Z
@@ -169,11 +169,11 @@ public function testHunkInvalidFormat(): void
 
     public function testHunkOverlapFrom(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected new hunk; "from" (\'-\') start overlaps previous hunk. Line 6.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected new hunk; "from" (\'-\') start overlaps previous hunk. Line 6.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8,1 +8,1 @@
 -Z
@@ -187,11 +187,11 @@ public function testHunkOverlapFrom(): void
 
     public function testHunkOverlapTo(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected new hunk; "to" (\'+\') start overlaps previous hunk. Line 6.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected new hunk; "to" (\'+\') start overlaps previous hunk. Line 6.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8,1 +8,1 @@
 -Z
@@ -205,11 +205,11 @@ public function testHunkOverlapTo(): void
 
     public function testExpectHunk1(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Expected hunk start (\'@\'), got "+". Line 6.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Expected hunk start (\'@\'), got "+". Line 6.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8 +8 @@
 -Z
@@ -221,11 +221,11 @@ public function testExpectHunk1(): void
 
     public function testExpectHunk2(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected hunk start (\'@\'). Line 6.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected hunk start (\'@\'). Line 6.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8,12 +8,12 @@
  ' . '
@@ -237,11 +237,11 @@ public function testExpectHunk2(): void
 
     public function testMisplacedLineAfterComments1(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected line as 2 "No newline" markers have found, ". Line 8.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected line as 2 "No newline" markers have found, ". Line 8.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8 +8 @@
 -Z
@@ -255,11 +255,11 @@ public function testMisplacedLineAfterComments1(): void
 
     public function testMisplacedLineAfterComments2(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected line as 2 "No newline" markers have found, ". Line 7.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected line as 2 "No newline" markers have found, ". Line 7.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8 +8 @@
 +U
@@ -272,11 +272,11 @@ public function testMisplacedLineAfterComments2(): void
 
     public function testMisplacedLineAfterComments3(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected line as 2 "No newline" markers have found, ". Line 7.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected line as 2 "No newline" markers have found, ". Line 7.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8 +8 @@
 +U
@@ -289,22 +289,22 @@ public function testMisplacedLineAfterComments3(): void
 
     public function testMisplacedComment(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected "\ No newline at end of file", it must be preceded by \'+\' or \'-\' line. Line 1.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected "\ No newline at end of file", it must be preceded by \'+\' or \'-\' line. Line 1.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'\ No newline at end of file
+            '\ No newline at end of file
 '
         );
     }
 
     public function testUnexpectedDuplicateNoNewLineEOF(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected "\\ No newline at end of file", "\\" was already closed. Line 8.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected "\\ No newline at end of file", "\\" was already closed. Line 8.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8,12 +8,12 @@
  ' . '
@@ -318,11 +318,11 @@ public function testUnexpectedDuplicateNoNewLineEOF(): void
 
     public function testFromAfterClose(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Not expected from (\'-\'), already closed by "\ No newline at end of file". Line 6.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Not expected from (\'-\'), already closed by "\ No newline at end of file". Line 6.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8,12 +8,12 @@
 -A
@@ -335,8 +335,8 @@ public function testFromAfterClose(): void
 
     public function testSameAfterFromClose(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Not expected same (\' \'), \'-\' already closed by "\ No newline at end of file". Line 6.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Not expected same (\' \'), \'-\' already closed by "\ No newline at end of file". Line 6.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
             '--- Original
@@ -352,8 +352,8 @@ public function testSameAfterFromClose(): void
 
     public function testToAfterClose(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Not expected to (\'+\'), already closed by "\ No newline at end of file". Line 6.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Not expected to (\'+\'), already closed by "\ No newline at end of file". Line 6.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
             '--- Original
@@ -369,8 +369,8 @@ public function testToAfterClose(): void
 
     public function testSameAfterToClose(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Not expected same (\' \'), \'+\' already closed by "\ No newline at end of file". Line 6.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Not expected same (\' \'), \'+\' already closed by "\ No newline at end of file". Line 6.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
             '--- Original
@@ -386,11 +386,11 @@ public function testSameAfterToClose(): void
 
     public function testUnexpectedEOFFromMissingLines(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected EOF, number of lines in hunk "from" (\'-\')) mismatched. Line 7.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected EOF, number of lines in hunk "from" (\'-\')) mismatched. Line 7.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8,19 +7,2 @@
 -A
@@ -402,11 +402,11 @@ public function testUnexpectedEOFFromMissingLines(): void
 
     public function testUnexpectedEOFToMissingLines(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected EOF, number of lines in hunk "to" (\'+\')) mismatched. Line 7.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected EOF, number of lines in hunk "to" (\'+\')) mismatched. Line 7.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -8,2 +7,3 @@
 -A
@@ -418,11 +418,11 @@ public function testUnexpectedEOFToMissingLines(): void
 
     public function testUnexpectedEOFBothFromAndToMissingLines(): void
     {
-        $this->expectException(\UnexpectedValueException::class);
-        $this->expectExceptionMessageRegExp(\sprintf('#^%s$#', \preg_quote('Unexpected EOF, number of lines in hunk "from" (\'-\')) and "to" (\'+\') mismatched. Line 7.', '#')));
+        $this->expectException(UnexpectedValueException::class);
+        $this->expectExceptionMessageRegExp(sprintf('#^%s$#', preg_quote('Unexpected EOF, number of lines in hunk "from" (\'-\')) and "to" (\'+\') mismatched. Line 7.', '#')));
 
         $this->assertValidUnifiedDiffFormat(
-'--- Original
+            '--- Original
 +++ New
 @@ -1,12 +1,14 @@
 -A
diff --git a/tools/composer-normalize b/tools/composer-normalize
new file mode 100755
index 00000000..86188d64
Binary files /dev/null and b/tools/composer-normalize differ
diff --git a/tools/php-cs-fixer b/tools/php-cs-fixer
new file mode 100755
index 00000000..859a4c38
Binary files /dev/null and b/tools/php-cs-fixer differ
diff --git a/tools/psalm b/tools/psalm
new file mode 100755
index 00000000..81abe7e1
Binary files /dev/null and b/tools/psalm differ
diff --git a/tools/roave-backward-compatibility-check b/tools/roave-backward-compatibility-check
new file mode 100755
index 00000000..f6fc5ec0
Binary files /dev/null and b/tools/roave-backward-compatibility-check differ