diff --git a/.github/workflows/code_analysis.yaml b/.github/workflows/code_analysis.yaml
index 45952c3..4c64dd8 100644
--- a/.github/workflows/code_analysis.yaml
+++ b/.github/workflows/code_analysis.yaml
@@ -4,13 +4,17 @@ on:
     pull_request: null
     push:
         branches:
-            - main
+            - master
 
 jobs:
     code_analysis:
         strategy:
             fail-fast: false
             matrix:
+                php:
+                    - "8.1"
+                    - "8.2"
+                    - "8.3"
                 actions:
                     -
                         name: "PHPStan"
@@ -20,19 +24,19 @@ jobs:
                         name: "PHPUnit"
                         run: vendor/bin/phpunit
 
-        name: ${{ matrix.actions.name }}
+        name: PHP${{ matrix.php }}:${{ matrix.actions.name }} 
         runs-on: ubuntu-latest
 
         steps:
-            -   uses: actions/checkout@v2
+            -   uses: actions/checkout@v4
 
             # see https://github.com/shivammathur/setup-php
             -   uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 7.4
+                    php-version: ${{ matrix.php }})
                     coverage: none
 
             # composer install cache - https://github.com/ramsey/composer-install
-            -   uses: "ramsey/composer-install@v1"
+            -   uses: "ramsey/composer-install@v2"
 
             -   run: ${{ matrix.actions.run }}
diff --git a/.gitignore b/.gitignore
index 47342dc..323486b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 composer.lock
 vendor/
 .phpunit.result.cache
+.phpunit.cache
diff --git a/composer.json b/composer.json
index 06b2e00..912a2ab 100644
--- a/composer.json
+++ b/composer.json
@@ -3,7 +3,11 @@
     "description": "Library for asserting things that happen asynchronously with PHPUnit",
     "license": "MIT",
     "type": "library",
-    "keywords": ["PHPUnit", "asynchronicity", "assertion"],
+    "keywords": [
+        "PHPUnit",
+        "asynchronicity",
+        "assertion"
+    ],
     "authors": [
         {
             "name": "Matthias Noback",
@@ -22,10 +26,11 @@
         }
     },
     "require": {
-        "php": "^7.3 || ^8.0"
+        "php": "^8.1"
     },
     "require-dev": {
-        "phpstan/phpstan": "^0.9.2",
-        "phpunit/phpunit": "^9.0"
+        "phpstan/phpstan": "^1.10",
+        "phpunit/phpunit": "^10.0",
+        "ext-pcntl": "*"
     }
-}
+}
\ No newline at end of file
diff --git a/phpstan.neon b/phpstan.neon
index 1494f51..47d35e5 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -3,3 +3,4 @@ parameters:
     paths:
         - src
         - tests
+    ignoreErrors: []
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index b5974e8..25c3806 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,17 +1,18 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit bootstrap="./vendor/autoload.php" colors="true">
-    <testsuites>
-        <testsuite name="Tests">
-            <directory suffix="Test.php">./tests</directory>
-        </testsuite>
-    </testsuites>
-    <filter>
-        <whitelist>
-            <directory>./</directory>
-            <exclude>
-                <directory>./tests</directory>
-                <directory>./vendor</directory>
-            </exclude>
-        </whitelist>
-    </filter>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" bootstrap="./vendor/autoload.php" colors="true" xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/10.4/phpunit.xsd" cacheDirectory=".phpunit.cache">
+  <coverage/>
+  <testsuites>
+    <testsuite name="Tests">
+      <directory suffix="Test.php">./tests</directory>
+    </testsuite>
+  </testsuites>
+  <source>
+    <include>
+      <directory>./</directory>
+    </include>
+    <exclude>
+      <directory>./tests</directory>
+      <directory>./vendor</directory>
+    </exclude>
+  </source>
 </phpunit>
diff --git a/src/Asynchronicity/PHPUnit/Eventually.php b/src/Asynchronicity/PHPUnit/Eventually.php
index dee05bc..9f0f7e4 100644
--- a/src/Asynchronicity/PHPUnit/Eventually.php
+++ b/src/Asynchronicity/PHPUnit/Eventually.php
@@ -3,6 +3,7 @@
 
 namespace Asynchronicity\PHPUnit;
 
+use Asynchronicity\Polling\IncorrectUsage;
 use Asynchronicity\Polling\Interrupted;
 use Asynchronicity\Polling\Poller;
 use Asynchronicity\Polling\SystemClock;
@@ -11,8 +12,8 @@
 
 final class Eventually extends Constraint
 {
-    private $timeoutMilliseconds;
-    private $waitMilliseconds;
+    private int $timeoutMilliseconds;
+    private int $waitMilliseconds;
 
     public function __construct(int $timeoutMilliseconds = 5000, int $waitMilliseconds = 500)
     {
@@ -20,8 +21,15 @@ public function __construct(int $timeoutMilliseconds = 5000, int $waitMillisecon
         $this->waitMilliseconds = $waitMilliseconds;
     }
 
-    public function evaluate($probe, string $description = '', bool $returnResult = false): ?bool
+    /**
+     * @throws Interrupted
+     */
+    public function evaluate(mixed $probe, string $description = '', bool $returnResult = false): ?bool
     {
+        if (!is_callable($probe)) {
+            throw new IncorrectUsage();
+        }
+
         try {
             $poller = new Poller();
             $poller->poll(
@@ -39,13 +47,13 @@ public function evaluate($probe, string $description = '', bool $returnResult =
         return true;
     }
 
-    protected function failureDescription($other): string
+    protected function failureDescription(mixed $other): string
     {
         return 'the given probe was satisfied within the provided timeout';
     }
 
     public function toString(): string
     {
-        throw new \BadMethodCallException('Not implemented');
+        return 'Eventually';
     }
-}
+}
\ No newline at end of file
diff --git a/tests/Asynchronicity/PHPUnit/EventuallyTest.php b/tests/Asynchronicity/PHPUnit/EventuallyTest.php
index 36aa343..4f9df66 100644
--- a/tests/Asynchronicity/PHPUnit/EventuallyTest.php
+++ b/tests/Asynchronicity/PHPUnit/EventuallyTest.php
@@ -10,10 +10,7 @@
 
 final class EventuallyTest extends TestCase
 {
-    /**
-     * @var Eventually
-     */
-    private $constraint;
+    private Eventually $constraint;
 
     /**
      * @var callable
@@ -101,6 +98,27 @@ public function it_accepts_a_closure_as_probe(): void
         }));
     }
 
+    /**
+     * @test
+     */
+    public function it_throws_an_exception_if_the_probe_is_not_callable(): void
+    {
+        $constraint = new Eventually();
+
+        $this->expectException(IncorrectUsage::class);
+        $constraint->evaluate('foobar');
+    }
+
+    /**
+     * @test
+     */
+    public function it_is_stringable(): void
+    {
+        $constraint = new Eventually();
+
+        $this->assertSame('Eventually', $constraint->toString());
+    }
+
     private function probeAlwaysFails(): void
     {
         $this->probe = function (): void {
diff --git a/tests/Asynchronicity/PHPUnit/FileHasBeenCreated.php b/tests/Asynchronicity/PHPUnit/FileHasBeenCreated.php
index 562a9a9..a48fa90 100644
--- a/tests/Asynchronicity/PHPUnit/FileHasBeenCreated.php
+++ b/tests/Asynchronicity/PHPUnit/FileHasBeenCreated.php
@@ -7,7 +7,7 @@
 
 final class FileHasBeenCreated
 {
-    private $path;
+    private string $path;
 
     public function __construct(string $path)
     {
diff --git a/tests/Asynchronicity/PHPUnit/IntegrationTest.php b/tests/Asynchronicity/PHPUnit/IntegrationTest.php
index 53de78b..46ff095 100644
--- a/tests/Asynchronicity/PHPUnit/IntegrationTest.php
+++ b/tests/Asynchronicity/PHPUnit/IntegrationTest.php
@@ -15,14 +15,14 @@ final class IntegrationTest extends TestCase
     public function it_waits_until_a_child_process_does_something(): void
     {
         if (!\extension_loaded('pcntl')) {
-            $this->markTestSkipped('Requires PCNTL extension');
+            self::markTestSkipped('Requires PCNTL extension');
         }
 
         $timeoutMilliseconds = 2000;
         $waitMilliseconds = 1000;
 
         $file = sys_get_temp_dir().'/'.uniqid('phpunit-asynchronicity', true);
-        $this->assertFileNotExists($file);
+        self::assertFileDoesNotExist($file);
 
         $pid = pcntl_fork();
         if ($pid === -1) {
diff --git a/tests/Asynchronicity/Polling/PollerTest.php b/tests/Asynchronicity/Polling/PollerTest.php
index 7a6e757..44f1561 100644
--- a/tests/Asynchronicity/Polling/PollerTest.php
+++ b/tests/Asynchronicity/Polling/PollerTest.php
@@ -4,11 +4,12 @@
 namespace Asynchronicity\Polling;
 
 use PHPUnit\Framework\Assert;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
 final class PollerTest extends TestCase
 {
-    private $waitTimeInMilliseconds = 1000;
+    private int $waitTimeInMilliseconds = 1000;
 
     /**
      * @var callable
@@ -21,7 +22,7 @@ final class PollerTest extends TestCase
     private $poller;
 
     /**
-     * @var Clock
+     * @var Clock&MockObject
      */
     private $clock;
 
diff --git a/tests/Asynchronicity/Polling/TimeoutTest.php b/tests/Asynchronicity/Polling/TimeoutTest.php
index 99779d3..56f214d 100644
--- a/tests/Asynchronicity/Polling/TimeoutTest.php
+++ b/tests/Asynchronicity/Polling/TimeoutTest.php
@@ -14,7 +14,7 @@ final class TimeoutTest extends TestCase
     private $timeout;
 
     /**
-     * @var MockObject & Clock
+     * @var MockObject&Clock
      */
     private $clock;
 
@@ -86,20 +86,14 @@ public function it_fails_when_start_is_not_called_first(): void
         $this->timeout->hasTimedOut();
     }
 
+    /**
+     * @param int[] $microtimes
+     */
     private function clockReturnsMicrotimes(array $microtimes): void
     {
-        static $at;
-        if ($at === null) {
-            $at = 0;
-        }
-
-        foreach ($microtimes as $microtime) {
-            $this->clock
-                ->expects($this->at($at))
-                ->method('getMicrotime')
-                ->will($this->returnValue($microtime));
-
-            $at++;
-        }
+        $this->clock
+            ->expects($this->exactly(count($microtimes)))
+            ->method('getMicrotime')
+            ->willReturnOnConsecutiveCalls(...$microtimes);
     }
 }