diff --git a/tests/ApplicationAvailabilityFunctionalTest.php b/tests/ApplicationAvailabilityFunctionalTest.php
index 0d94a9e0..4825cf27 100644
--- a/tests/ApplicationAvailabilityFunctionalTest.php
+++ b/tests/ApplicationAvailabilityFunctionalTest.php
@@ -42,7 +42,6 @@ declare(strict_types=1);
 
 namespace App\Tests;
 
-use App\Entity\Parts\Manufacturer;
 use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
 
 /**
diff --git a/tests/DatatablesAvailabilityTest.php b/tests/DatatablesAvailabilityTest.php
index 4093c616..2ef73de1 100644
--- a/tests/DatatablesAvailabilityTest.php
+++ b/tests/DatatablesAvailabilityTest.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
  *
@@ -20,16 +23,14 @@
 
 namespace App\Tests;
 
-
 use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
 
 class DatatablesAvailabilityTest extends WebTestCase
 {
     /**
      * @dataProvider urlProvider
-     * @param  string  $url
      */
-    public function testDataTable(string $url)
+    public function testDataTable(string $url): void
     {
         //We have localized routes
         $url = '/en'.$url;
@@ -63,6 +64,5 @@ class DatatablesAvailabilityTest extends WebTestCase
         yield ['/log/'];
 
         yield ['/attachment/list'];
-
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Entity/LogSystem/AbstractLogEntryTest.php b/tests/Entity/LogSystem/AbstractLogEntryTest.php
index 1e2b9ef7..f20aacd2 100644
--- a/tests/Entity/LogSystem/AbstractLogEntryTest.php
+++ b/tests/Entity/LogSystem/AbstractLogEntryTest.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
  *
@@ -24,6 +27,7 @@ use App\Entity\Attachments\Attachment;
 use App\Entity\Attachments\AttachmentType;
 use App\Entity\Attachments\PartAttachment;
 use App\Entity\Devices\Device;
+use App\Entity\Devices\DevicePart;
 use App\Entity\LogSystem\AbstractLogEntry;
 use App\Entity\Parts\Category;
 use App\Entity\Parts\Footprint;
@@ -34,11 +38,9 @@ use App\Entity\Parts\Supplier;
 use App\Entity\UserSystem\Group;
 use App\Entity\UserSystem\User;
 use PHPUnit\Framework\TestCase;
-use App\Entity\Devices\DevicePart;
 
 class AbstractLogEntryTest extends TestCase
 {
-
     public function levelDataProvider(): array
     {
         return [
@@ -51,7 +53,7 @@ class AbstractLogEntryTest extends TestCase
             [6, 'info'],
             [7, 'debug'],
             [8, 'blabla', true],
-            [-1, 'test', true]
+            [-1, 'test', true],
         ];
     }
 
@@ -70,14 +72,14 @@ class AbstractLogEntryTest extends TestCase
             [10, Part::class],
             [11, Storelocation::class],
             [12, Supplier::class],
-            [-1, 'blablub', true]
+            [-1, 'blablub', true],
         ];
     }
 
     /**
      * @dataProvider levelDataProvider
      */
-    public function testLevelIntToString(int $int, string $expected_string, bool $expect_exception = false)
+    public function testLevelIntToString(int $int, string $expected_string, bool $expect_exception = false): void
     {
         if ($expect_exception) {
             $this->expectException(\InvalidArgumentException::class);
@@ -88,7 +90,7 @@ class AbstractLogEntryTest extends TestCase
     /**
      * @dataProvider levelDataProvider
      */
-    public function testLevelStringToInt(int $expected_int, string $string, bool $expect_exception = false)
+    public function testLevelStringToInt(int $expected_int, string $string, bool $expect_exception = false): void
     {
         if ($expect_exception) {
             $this->expectException(\InvalidArgumentException::class);
@@ -99,7 +101,7 @@ class AbstractLogEntryTest extends TestCase
     /**
      * @dataProvider targetTypeDataProvider
      */
-    public function testTargetTypeIdToClass(int $int, string $expected_class, bool $expect_exception = false)
+    public function testTargetTypeIdToClass(int $int, string $expected_class, bool $expect_exception = false): void
     {
         if ($expect_exception) {
             $this->expectException(\InvalidArgumentException::class);
@@ -110,7 +112,7 @@ class AbstractLogEntryTest extends TestCase
     /**
      * @dataProvider targetTypeDataProvider
      */
-    public function testTypeClassToID(int $expected_id, string $class, bool $expect_exception = false)
+    public function testTypeClassToID(int $expected_id, string $class, bool $expect_exception = false): void
     {
         if ($expect_exception) {
             $this->expectException(\InvalidArgumentException::class);
@@ -118,18 +120,19 @@ class AbstractLogEntryTest extends TestCase
         $this->assertSame($expected_id, AbstractLogEntry::targetTypeClassToID($class));
     }
 
-    public function testTypeClassToIDSubclasses()
+    public function testTypeClassToIDSubclasses(): void
     {
         //Test if class mapping works for subclasses
         $this->assertSame(2, AbstractLogEntry::targetTypeClassToID(PartAttachment::class));
     }
 
-    public function testSetGetTarget()
+    public function testSetGetTarget(): void
     {
         $part = $this->createMock(Part::class);
         $part->method('getID')->willReturn(10);
 
-        $log = new class extends AbstractLogEntry {};
+        $log = new class() extends AbstractLogEntry {
+        };
         $log->setTargetElement($part);
 
         $this->assertSame(Part::class, $log->getTargetClass());
diff --git a/tests/Entity/Parameters/PartParameterTest.php b/tests/Entity/Parameters/PartParameterTest.php
index 1d04b1b0..ee90a761 100644
--- a/tests/Entity/Parameters/PartParameterTest.php
+++ b/tests/Entity/Parameters/PartParameterTest.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
  *
@@ -25,7 +28,6 @@ use PHPUnit\Framework\TestCase;
 
 class PartParameterTest extends TestCase
 {
-
     public function valueWithUnitDataProvider(): array
     {
         return [
@@ -53,9 +55,6 @@ class PartParameterTest extends TestCase
 
     /**
      * @dataProvider  valueWithUnitDataProvider
-     * @param  string  $expected
-     * @param  float  $value
-     * @param  string  $unit
      */
     public function testGetValueMinWithUnit(string $expected, float $value, string $unit): void
     {
@@ -67,9 +66,6 @@ class PartParameterTest extends TestCase
 
     /**
      * @dataProvider  valueWithUnitDataProvider
-     * @param  string  $expected
-     * @param  float  $value
-     * @param  string  $unit
      */
     public function testGetValueMaxWithUnit(string $expected, float $value, string $unit): void
     {
@@ -81,9 +77,6 @@ class PartParameterTest extends TestCase
 
     /**
      * @dataProvider  valueWithUnitDataProvider
-     * @param  string  $expected
-     * @param  float  $value
-     * @param  string  $unit
      */
     public function testGetValueTypicalWithUnit(string $expected, float $value, string $unit): void
     {
@@ -95,12 +88,10 @@ class PartParameterTest extends TestCase
 
     /**
      * @dataProvider formattedValueDataProvider
-     * @param  string  $expected
-     * @param  float  $min
-     * @param  float  $typical
-     * @param  float  $max
-     * @param  string  $unit
-     * @param  string  $text
+     *
+     * @param float $min
+     * @param float $typical
+     * @param float $max
      */
     public function testGetFormattedValue(string $expected, ?float $min, ?float $typical, ?float $max, string $unit, string $text): void
     {
diff --git a/tests/Services/LogSystem/EventCommentHelperTest.php b/tests/Services/LogSystem/EventCommentHelperTest.php
index 8ce44503..18bdfcb8 100644
--- a/tests/Services/LogSystem/EventCommentHelperTest.php
+++ b/tests/Services/LogSystem/EventCommentHelperTest.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
  *
@@ -21,8 +24,6 @@
 namespace App\Tests\Services\LogSystem;
 
 use App\Services\LogSystem\EventCommentHelper;
-use App\Services\LogSystem\EventLogger;
-use PHPUnit\Framework\TestCase;
 use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
 
 class EventCommentHelperTest extends WebTestCase
@@ -41,13 +42,13 @@ class EventCommentHelperTest extends WebTestCase
         $this->service = self::$container->get(EventCommentHelper::class);
     }
 
-    public function testInitialState()
+    public function testInitialState(): void
     {
         $this->assertNull($this->service->getMessage());
         $this->assertFalse($this->service->isMessageSet());
     }
 
-    public function testClearMessage()
+    public function testClearMessage(): void
     {
         $this->service->setMessage('Test');
         $this->assertTrue($this->service->isMessageSet());
@@ -55,13 +56,13 @@ class EventCommentHelperTest extends WebTestCase
         $this->assertFalse($this->service->isMessageSet());
     }
 
-    public function testGetSetMessage()
+    public function testGetSetMessage(): void
     {
         $this->service->setMessage('Test');
         $this->assertSame('Test', $this->service->getMessage());
     }
 
-    public function testIsMessageSet()
+    public function testIsMessageSet(): void
     {
         $this->service->setMessage('Test');
         $this->assertTrue($this->service->isMessageSet());
diff --git a/tests/Services/LogSystem/EventLoggerTest.php b/tests/Services/LogSystem/EventLoggerTest.php
index a6fa0884..6d87b505 100644
--- a/tests/Services/LogSystem/EventLoggerTest.php
+++ b/tests/Services/LogSystem/EventLoggerTest.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
  *
@@ -28,7 +31,6 @@ use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
 
 class EventLoggerTest extends WebTestCase
 {
-
     /**
      * @var EventLogger
      */
@@ -43,13 +45,12 @@ class EventLoggerTest extends WebTestCase
         $this->service = self::$container->get(EventLogger::class);
     }
 
-    public function testShouldBeAdded()
+    public function testShouldBeAdded(): void
     {
         $event1 = new UserLoginLogEntry('127.0.0.1');
         $event2 = new UserLogoutLogEntry('127.0.0.1');
         $event2->setLevel(AbstractLogEntry::LEVEL_CRITICAL);
 
-
         //Test without restrictions
         $this->assertTrue($this->service->shouldBeAdded($event1, 7, [], []));