Enhancement: Implement ConfigHashNormalizer

README.md

@@ -13,6 +13,19 @@ Run
 $ composer global require localheinz/composer-normalize
 ```
 
+## Usage
+
+This package comes with the following normalizers:
+
+* [`Localheinz\Composer\Normalize\Normalizer\ConfigHashNormalizer`](#confighashnormalizer)
+
+### `ConfigHashNormalizer`
+
+If `composer.json` contains any configuration in the `config` section, 
+the `ConfigHashNormalizer` will sort the `config` section by key in ascending order.
+
+:bulb: Find out more about the `config` section at https://getcomposer.org/doc/06-config.md.  
+
 ## Contributing
 
 Please have a look at [`CONTRIBUTING.md`](.github/CONTRIBUTING.md).

src/Normalizer/ConfigHashNormalizer.php

@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2018 Andreas Möller.
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * @see https://github.com/localheinz/composer-normalize
+ */
+
+namespace Localheinz\Composer\Normalize\Normalizer;
+
+use Localheinz\Json\Normalizer\NormalizerInterface;
+
+final class ConfigHashNormalizer implements NormalizerInterface
+{
+    public function normalize(string $json): string
+    {
+        $decoded = \json_decode($json);
+
+        if (null === $decoded && JSON_ERROR_NONE !== \json_last_error()) {
+            throw new \InvalidArgumentException(\sprintf(
+                '"%s" is not valid JSON.',
+                $json
+            ));
+        }
+
+        if (!\property_exists($decoded, 'config')) {
+            return $json;
+        }
+
+        $config = (array) $decoded->config;
+
+        \ksort($config);
+
+        $decoded->config = $config;
+
+        return \json_encode($decoded);
+    }
+}

test/Unit/Normalizer/AbstractNormalizerTestCase.php

@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2018 Andreas Möller.
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * @see https://github.com/localheinz/composer-normalize
+ */
+
+namespace Localheinz\Composer\Normalize\Test\Unit\Normalizer;
+
+use Localheinz\Json\Normalizer\NormalizerInterface;
+use Localheinz\Test\Util\Helper;
+use PHPUnit\Framework;
+
+abstract class AbstractNormalizerTestCase extends Framework\TestCase
+{
+    use Helper;
+
+    final public function testImplementsNormalizerInterface()
+    {
+        $this->assertClassImplementsInterface(NormalizerInterface::class, $this->className());
+    }
+
+    final public function testNormalizeRejectsInvalidJson()
+    {
+        $json = $this->faker()->realText();
+
+        $reflection = new \ReflectionClass($this->className());
+
+        $normalizer = $reflection->newInstanceWithoutConstructor();
+
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage(\sprintf(
+            '"%s" is not valid JSON.',
+            $json
+        ));
+
+        $normalizer->normalize($json);
+    }
+
+    final protected function className(): string
+    {
+        return \preg_replace(
+            '/Test$/',
+            '',
+            \str_replace(
+                'Localheinz\\Composer\\Normalize\\Test\\Unit\\',
+                'Localheinz\\Composer\\Normalize\\',
+                static::class
+            )
+        );
+    }
+}

test/Unit/Normalizer/ConfigHashNormalizerTest.php

@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright (c) 2018 Andreas Möller.
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ *
+ * @see https://github.com/localheinz/composer-normalize
+ */
+
+namespace Localheinz\Composer\Normalize\Test\Unit\Normalizer;
+
+use Localheinz\Composer\Normalize\Normalizer\ConfigHashNormalizer;
+
+final class ConfigHashNormalizerTest extends AbstractNormalizerTestCase
+{
+    public function testNormalizeDoesNotModifyOtherProperty()
+    {
+        $json = <<<'JSON'
+{
+  "foo": {
+    "qux": "quux",
+    "bar": "baz"
+  }
+}
+JSON;
+
+        $normalizer = new ConfigHashNormalizer();
+
+        $this->assertSame($json, $normalizer->normalize($json));
+    }
+
+    public function testNormalizeSortsConfigHashIfPropertyExists()
+    {
+        $json = <<<'JSON'
+{
+  "config": {
+    "sort-packages": true,
+    "preferred-install": "dist"
+  },
+  "foo": {
+    "qux": "quux",
+    "bar": "baz"
+  }  
+}
+JSON;
+
+        $normalized = <<<'JSON'
+{
+  "config": {
+    "preferred-install": "dist",
+    "sort-packages": true
+  },
+  "foo": {
+    "qux": "quux",
+    "bar": "baz"
+  }
+}
+JSON;
+
+        $normalizer = new ConfigHashNormalizer();
+
+        $this->assertSame(\json_encode(\json_decode($normalized)), $normalizer->normalize($json));
+    }
+}