diff --git a/README.md b/README.md
index f90252cb..5611e34a 100644
--- a/README.md
+++ b/README.md
@@ -173,7 +173,7 @@ implementations or create/extend your own implementation.
 #### FlockMutex
 
 The **FlockMutex** is a lock implementation based on
-[`flock()`](http://php.net/manual/en/function.flock.php).
+[`flock()`](https://php.net/manual/en/function.flock.php).
 
 Example:
 ```php
@@ -194,7 +194,7 @@ extension if possible or busy waiting if not.
 #### MemcachedMutex
 
 The **MemcachedMutex** is a spinlock implementation which uses the
-[`Memcached` extension](http://php.net/manual/en/book.memcached.php).
+[`Memcached` extension](https://php.net/manual/en/book.memcached.php).
 
 Example:
 ```php
@@ -215,7 +215,7 @@ $mutex->synchronized(function () use ($bankAccount, $amount) {
 #### RedisMutex
 
 The **RedisMutex** is the distributed lock implementation of
-[RedLock](http://redis.io/topics/distlock) which supports the
+[RedLock](https://redis.io/topics/distlock#the-redlock-algorithm) which supports the
 [`phpredis` extension](https://github.com/phpredis/phpredis)
 or [`Predis` API](https://github.com/nrk/predis).
 
@@ -244,7 +244,7 @@ $mutex->synchronized(function () use ($bankAccount, $amount) {
 #### SemaphoreMutex
 
 The **SemaphoreMutex** is a lock implementation based on
-[Semaphore](http://php.net/manual/en/ref.sem.php).
+[Semaphore](https://php.net/manual/en/ref.sem.php).
 
 Example:
 ```php
@@ -330,9 +330,9 @@ Commercial support is available.
 
 This project is free and is licensed under the MIT.
 
-[1]: http://semver.org/
+[1]: https://semver.org/
 [2]: https://github.com/nrk/predis
-[3]: http://php.net/manual/en/book.pcntl.php
+[3]: https://php.net/manual/en/book.pcntl.php
 [4]: https://getcomposer.org/
 [5]: https://github.com/php-lock/lock/blob/3ca295ccda/src/Mutex/Mutex.php#L15
 [6]: https://github.com/php-lock/lock/blob/3ca295ccda/src/Mutex/Mutex.php#L38
diff --git a/src/Exception/ExecutionOutsideLockException.php b/src/Exception/ExecutionOutsideLockException.php
index 54916eef..ed848365 100644
--- a/src/Exception/ExecutionOutsideLockException.php
+++ b/src/Exception/ExecutionOutsideLockException.php
@@ -9,8 +9,9 @@
 
 /**
  * This exception should be thrown when for example the lock is released or the
- * lock times out before the critical code has finished execution. This is a
- * serious exception. Side effects might have happened while the critical code
+ * lock times out before the critical code has finished execution.
+ *
+ * This is a serious exception. Side effects might have happened while the critical code
  * was executed outside of the lock which should not be trusted to be valid.
  *
  * Should only be used in contexts where the lock is being released.
diff --git a/src/Mutex/AbstractRedlockMutex.php b/src/Mutex/AbstractRedlockMutex.php
index e0524ea5..5929e003 100644
--- a/src/Mutex/AbstractRedlockMutex.php
+++ b/src/Mutex/AbstractRedlockMutex.php
@@ -16,7 +16,9 @@
  *
  * @template TClient of object
  *
- * @see http://redis.io/topics/distlock
+ * @internal
+ *
+ * @see https://redis.io/topics/distlock#the-redlock-algorithm
  */
 abstract class AbstractRedlockMutex extends AbstractSpinlockWithTokenMutex implements LoggerAwareInterface
 {
diff --git a/src/Mutex/Mutex.php b/src/Mutex/Mutex.php
index dbd95978..dbeb4a06 100644
--- a/src/Mutex/Mutex.php
+++ b/src/Mutex/Mutex.php
@@ -38,8 +38,7 @@ public function synchronized(callable $code);
     /**
      * Performs a double-checked locking pattern.
      *
-     * Call {@link \Malkusch\Lock\Util\DoubleCheckedLocking::then()} on the
-     * returned object.
+     * Call {@link DoubleCheckedLocking::then()} on the returned object.
      *
      * Example:
      * <code>
diff --git a/src/Mutex/MySQLMutex.php b/src/Mutex/MySQLMutex.php
index 81460944..d21cd63a 100644
--- a/src/Mutex/MySQLMutex.php
+++ b/src/Mutex/MySQLMutex.php
@@ -27,7 +27,7 @@ public function __construct(\PDO $PDO, string $name, float $acquireTimeout = 0)
         $namePrefix = LockUtil::getInstance()->getKeyPrefix() . ':';
 
         if (\strlen($name) > 64 - \strlen($namePrefix)) {
-            throw new \InvalidArgumentException('The maximum length of the lock name is ' . (64 - \strlen($namePrefix)) . ' characters');
+            throw new \InvalidArgumentException('The maximum length of the database lock name is ' . (64 - \strlen($namePrefix)) . ' characters');
         }
 
         $this->name = $namePrefix . $name;
diff --git a/src/Mutex/NoMutex.php b/src/Mutex/NullMutex.php
similarity index 50%
rename from src/Mutex/NoMutex.php
rename to src/Mutex/NullMutex.php
index 881dd1ef..56830ec4 100644
--- a/src/Mutex/NoMutex.php
+++ b/src/Mutex/NullMutex.php
@@ -5,12 +5,9 @@
 namespace Malkusch\Lock\Mutex;
 
 /**
- * This mutex doesn't lock at all.
- *
- * Synchronization is not provided! This mutex is just implementing the
- * interface without locking.
+ * This mutex does not lock at all.
  */
-class NoMutex extends AbstractMutex
+class NullMutex extends AbstractMutex
 {
     #[\Override]
     public function synchronized(callable $code)
diff --git a/src/Mutex/RedisMutex.php b/src/Mutex/RedisMutex.php
index 19caf68d..b154ace2 100644
--- a/src/Mutex/RedisMutex.php
+++ b/src/Mutex/RedisMutex.php
@@ -17,7 +17,7 @@
  *
  * @extends AbstractRedlockMutex<TClient>
  *
- * @see http://redis.io/topics/distlock
+ * @see https://redis.io/topics/distlock#the-redlock-algorithm
  */
 class RedisMutex extends AbstractRedlockMutex
 {
@@ -122,7 +122,7 @@ protected function evalScript(object $client, string $luaScript, array $keys, ar
             }
         } else {
             try {
-                return $client->eval($luaScript, count($keys), ...[...$keys, ...$arguments]);
+                return $client->eval($luaScript, count($keys), ...$keys, ...$arguments);
             } catch (PredisException $e) {
                 throw new LockReleaseException('Failed to release lock', 0, $e);
             }
diff --git a/src/Mutex/SemaphoreMutex.php b/src/Mutex/SemaphoreMutex.php
index 80d3f3cf..a1f4bece 100644
--- a/src/Mutex/SemaphoreMutex.php
+++ b/src/Mutex/SemaphoreMutex.php
@@ -12,11 +12,11 @@
  */
 class SemaphoreMutex extends AbstractLockMutex
 {
-    /** @var \SysvSemaphore|resource The semaphore id */
+    /** @var \SysvSemaphore|resource */
     private $semaphore;
 
     /**
-     * Use {@link sem_get()} to create the semaphore id.
+     * Use {@link sem_get()} to create the semaphore.
      *
      * Example:
      * <code>
@@ -24,7 +24,7 @@ class SemaphoreMutex extends AbstractLockMutex
      * $mutex = new SemaphoreMutex($semaphore);
      * </code>
      *
-     * @param \SysvSemaphore|resource $semaphore The semaphore id
+     * @param \SysvSemaphore|resource $semaphore
      */
     public function __construct($semaphore)
     {
diff --git a/src/Util/DoubleCheckedLocking.php b/src/Util/DoubleCheckedLocking.php
index 51deabdd..d45f1794 100644
--- a/src/Util/DoubleCheckedLocking.php
+++ b/src/Util/DoubleCheckedLocking.php
@@ -12,7 +12,7 @@
  * The double-checked locking pattern.
  *
  * You should not instantiate this class directly. Use
- * {@link \Malkusch\Lock\Mutex\Mutex::check()}.
+ * {@link Mutex::check()}.
  *
  * @internal
  */
@@ -24,9 +24,8 @@ class DoubleCheckedLocking
     private $check;
 
     /**
-     * @param Mutex            $mutex Provides methods for exclusive code execution
-     * @param callable(): bool $check Callback that decides if the lock should be acquired and if the critical code
-     *                                callback should be executed after acquiring the lock
+     * @param callable(): bool $check Callback that decides if the lock should be acquired and is rechecked
+     *                                after a lock has been acquired
      */
     public function __construct(Mutex $mutex, callable $check)
     {
@@ -35,17 +34,12 @@ public function __construct(Mutex $mutex, callable $check)
     }
 
     /**
-     * Executes a synchronized callback only after the check callback passes
-     * before and after acquiring the lock.
-     *
-     * If then returns boolean boolean false, the check did not pass before or
-     * after acquiring the lock. A boolean false can also be returned from the
-     * critical code callback to indicate that processing did not occure or has
-     * failed. It is up to the user to decide the last point.
+     * Executes a block of code only after the check callback passes
+     * before and after acquiring a lock.
      *
      * @template T
      *
-     * @param callable(): T $code The critical code callback
+     * @param callable(): T $code
      *
      * @return T|false False if check did not pass
      *
diff --git a/src/Util/Loop.php b/src/Util/Loop.php
index ffae548d..5a2cca42 100644
--- a/src/Util/Loop.php
+++ b/src/Util/Loop.php
@@ -23,7 +23,7 @@ class Loop
     private bool $looping = false;
 
     /**
-     * Notifies that this was the last iteration.
+     * Notify that this was the last iteration.
      */
     public function end(): void
     {
@@ -35,7 +35,7 @@ public function end(): void
      *
      * The code has to be designed in a way that it can be repeated without any
      * side effects. When execution was successful it should notify that event
-     * by calling {@link \Malkusch\Lock\Util\Loop::end()}. I.e. the only side
+     * by calling {@link Loop::end()}. I.e. the only side
      * effects of the code may happen after a successful execution.
      *
      * If the code throws an exception it will stop repeating the execution.
diff --git a/tests/Mutex/FlockMutexTest.php b/tests/Mutex/FlockMutexTest.php
index 164b78ee..63c70437 100644
--- a/tests/Mutex/FlockMutexTest.php
+++ b/tests/Mutex/FlockMutexTest.php
@@ -11,6 +11,7 @@
 use Malkusch\Lock\Util\LockUtil;
 use Malkusch\Lock\Util\PcntlTimeout;
 use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\Attributes\RequiresPhpExtension;
 use PHPUnit\Framework\TestCase;
 
 class FlockMutexTest extends TestCase
@@ -18,8 +19,7 @@ class FlockMutexTest extends TestCase
     /** @var FlockMutex */
     private $mutex;
 
-    /** @var string */
-    private $file;
+    private string $file;
 
     #[\Override]
     protected function setUp(): void
@@ -88,10 +88,17 @@ static function () {
      */
     public static function provideTimeoutableStrategiesCases(): iterable
     {
-        yield [\Closure::bind(static fn () => FlockMutex::STRATEGY_PCNTL, null, FlockMutex::class)()];
+        if (extension_loaded('pcntl')) {
+            yield [\Closure::bind(static fn () => FlockMutex::STRATEGY_PCNTL, null, FlockMutex::class)()];
+        }
+
         yield [\Closure::bind(static fn () => FlockMutex::STRATEGY_LOOP, null, FlockMutex::class)()];
     }
 
+    /**
+     * @requires extension pcntl
+     */
+    #[RequiresPhpExtension('pcntl')]
     public function testNoTimeoutWaitsForever(): void
     {
         $this->expectException(DeadlineException::class);
diff --git a/tests/Mutex/MutexConcurrencyTest.php b/tests/Mutex/MutexConcurrencyTest.php
index cf31834c..0477eda4 100644
--- a/tests/Mutex/MutexConcurrencyTest.php
+++ b/tests/Mutex/MutexConcurrencyTest.php
@@ -159,13 +159,15 @@ public static function provideExecutionIsSerializedWhenLockedCases(): iterable
             return new FlockMutex($file, $timeout);
         }];
 
-        yield 'flockWithTimoutPcntl' => [static function ($timeout) use ($filename): Mutex {
-            $file = fopen($filename, 'w');
-            $lock = Liberator::liberate(new FlockMutex($file, $timeout));
-            $lock->strategy = \Closure::bind(static fn () => FlockMutex::STRATEGY_PCNTL, null, FlockMutex::class)(); // @phpstan-ignore property.notFound
+        if (extension_loaded('pcntl')) {
+            yield 'flockWithTimoutPcntl' => [static function ($timeout) use ($filename): Mutex {
+                $file = fopen($filename, 'w');
+                $lock = Liberator::liberate(new FlockMutex($file, $timeout));
+                $lock->strategy = \Closure::bind(static fn () => FlockMutex::STRATEGY_PCNTL, null, FlockMutex::class)(); // @phpstan-ignore property.notFound
 
-            return $lock->popsValue();
-        }];
+                return $lock->popsValue();
+            }];
+        }
 
         yield 'flockWithTimoutLoop' => [static function ($timeout) use ($filename): Mutex {
             $file = fopen($filename, 'w');
diff --git a/tests/Mutex/MutexTest.php b/tests/Mutex/MutexTest.php
index 42e82421..ca4eb18b 100644
--- a/tests/Mutex/MutexTest.php
+++ b/tests/Mutex/MutexTest.php
@@ -11,7 +11,7 @@
 use Malkusch\Lock\Mutex\MemcachedMutex;
 use Malkusch\Lock\Mutex\Mutex;
 use Malkusch\Lock\Mutex\MySQLMutex;
-use Malkusch\Lock\Mutex\NoMutex;
+use Malkusch\Lock\Mutex\NullMutex;
 use Malkusch\Lock\Mutex\PostgreSQLMutex;
 use Malkusch\Lock\Mutex\RedisMutex;
 use Malkusch\Lock\Mutex\SemaphoreMutex;
@@ -46,8 +46,8 @@ public static function setUpBeforeClass(): void
      */
     public static function provideMutexFactoriesCases(): iterable
     {
-        yield 'NoMutex' => [static function (): Mutex {
-            return new NoMutex();
+        yield 'NullMutex' => [static function (): Mutex {
+            return new NullMutex();
         }];
 
         yield 'FlockMutex' => [static function (): Mutex {
@@ -56,13 +56,15 @@ public static function provideMutexFactoriesCases(): iterable
             return new FlockMutex($file);
         }];
 
-        yield 'flockWithTimoutPcntl' => [static function (): Mutex {
-            $file = fopen(vfsStream::url('test/lock'), 'w');
-            $lock = Liberator::liberate(new FlockMutex($file, 3));
-            $lock->strategy = \Closure::bind(static fn () => FlockMutex::STRATEGY_PCNTL, null, FlockMutex::class)(); // @phpstan-ignore property.notFound
+        if (extension_loaded('pcntl')) {
+            yield 'flockWithTimoutPcntl' => [static function (): Mutex {
+                $file = fopen(vfsStream::url('test/lock'), 'w');
+                $lock = Liberator::liberate(new FlockMutex($file, 3));
+                $lock->strategy = \Closure::bind(static fn () => FlockMutex::STRATEGY_PCNTL, null, FlockMutex::class)(); // @phpstan-ignore property.notFound
 
-            return $lock->popsValue();
-        }];
+                return $lock->popsValue();
+            }];
+        }
 
         yield 'flockWithTimoutLoop' => [static function (): Mutex {
             $file = fopen(vfsStream::url('test/lock'), 'w');
diff --git a/tests/Util/LoopTest.php b/tests/Util/LoopTest.php
index 2b93523f..9fb020b5 100644
--- a/tests/Util/LoopTest.php
+++ b/tests/Util/LoopTest.php
@@ -64,12 +64,10 @@ public static function provideInvalidAcquireTimeoutCases(): iterable
     }
 
     /**
-     * Tests execution within the timeout.
-     *
      * @doesNotPerformAssertions
      */
     #[DoesNotPerformAssertions]
-    public function testExecutionWithinTimeout(): void
+    public function testExecutionWithinAcquireTimeout(): void
     {
         $loop = new Loop();
         $loop->execute(static function () use ($loop): void {
@@ -78,10 +76,7 @@ public function testExecutionWithinTimeout(): void
         }, 0.5);
     }
 
-    /**
-     * Tests execution within the timeout without calling end().
-     */
-    public function testExecutionWithinAcquireTimeoutWithoutExplicitEnd(): void
+    public function testExecutionWithinAcquireTimeoutWithoutCallingEnd(): void
     {
         $this->expectException(LockAcquireTimeoutException::class);
         $this->expectExceptionMessage('Lock acquire timeout of 0.5 seconds has been exceeded');
@@ -93,12 +88,10 @@ public function testExecutionWithinAcquireTimeoutWithoutExplicitEnd(): void
     }
 
     /**
-     * Tests exceeding the execution timeout.
-     *
      * @doesNotPerformAssertions
      */
     #[DoesNotPerformAssertions]
-    public function testExceedTimeoutIsAcceptableIfEndWasCalled(): void
+    public function testExceedAcquireTimeoutIsAcceptableIfEndWasCalled(): void
     {
         $loop = new Loop();
         $loop->execute(static function () use ($loop): void {
@@ -107,10 +100,7 @@ public function testExceedTimeoutIsAcceptableIfEndWasCalled(): void
         }, 0.5);
     }
 
-    /**
-     * Tests exceeding the execution timeout without calling end().
-     */
-    public function testExceedAcquireTimeoutWithoutExplicitEnd(): void
+    public function testExceedAcquireTimeoutWithoutCallingEnd(): void
     {
         $this->expectException(LockAcquireTimeoutException::class);
         $this->expectExceptionMessage('Lock acquire timeout of 0.5 seconds has been exceeded');
@@ -121,9 +111,6 @@ public function testExceedAcquireTimeoutWithoutExplicitEnd(): void
         }, 0.5);
     }
 
-    /**
-     * Tests that an exception would stop any further iteration.
-     */
     public function testExceptionStopsIteration(): void
     {
         $this->expectException(\DomainException::class);
@@ -134,10 +121,7 @@ public function testExceptionStopsIteration(): void
         }, 1);
     }
 
-    /**
-     * Tests end() will stop the iteration and return the result.
-     */
-    public function testEnd(): void
+    public function testEndCodeExecutedOnce(): void
     {
         $i = 0;
         $loop = new Loop();
@@ -148,10 +132,7 @@ public function testEnd(): void
         self::assertSame(1, $i);
     }
 
-    /**
-     * Tests that the code is executed more times.
-     */
-    public function testIteration(): void
+    public function testEndCodeExecutedTwice(): void
     {
         $i = 0;
         $loop = new Loop();