diff --git a/src/Entity/PriceInformations/Pricedetail.php b/src/Entity/PriceInformations/Pricedetail.php
index ce719b11..be5d4276 100644
--- a/src/Entity/PriceInformations/Pricedetail.php
+++ b/src/Entity/PriceInformations/Pricedetail.php
@@ -280,6 +280,7 @@ class Pricedetail extends DBElement
      * quantity to 100. The single price (20$/100 = 0.2$) will be calculated automatically.
      *
      * @param float $new_price_related_quantity the price related quantity
+     * @return $this
      */
     public function setPriceRelatedQuantity(float $new_price_related_quantity): self
     {
diff --git a/tests/ApplicationAvailabilityFunctionalTest.php b/tests/ApplicationAvailabilityFunctionalTest.php
index 321b9db2..6d61a9f6 100644
--- a/tests/ApplicationAvailabilityFunctionalTest.php
+++ b/tests/ApplicationAvailabilityFunctionalTest.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).
  *
diff --git a/tests/Controller/AdminPages/AbstractAdminControllerTest.php b/tests/Controller/AdminPages/AbstractAdminControllerTest.php
index a9da3b73..bc269d0d 100644
--- a/tests/Controller/AdminPages/AbstractAdminControllerTest.php
+++ b/tests/Controller/AdminPages/AbstractAdminControllerTest.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).
  *
@@ -48,7 +51,7 @@ abstract class AbstractAdminControllerTest extends WebTestCase
      * @group slow
      * Tests if you can access the /new part which is used to list all entities. Checks if permissions are working
      */
-    public function testListEntries(string $user, bool $read)
+    public function testListEntries(string $user, bool $read): void
     {
         static::ensureKernelShutdown();
 
@@ -58,7 +61,7 @@ abstract class AbstractAdminControllerTest extends WebTestCase
             'PHP_AUTH_PW' => 'test',
         ]);
 
-        if (false == $read) {
+        if (false === $read) {
             $this->expectException(AccessDeniedException::class);
         }
 
@@ -67,8 +70,8 @@ abstract class AbstractAdminControllerTest extends WebTestCase
         //Test read/list access by access /new overview page
         $crawler = $client->request('GET', static::$base_path.'/new');
         $this->assertFalse($client->getResponse()->isRedirect());
-        $this->assertEquals($read, $client->getResponse()->isSuccessful(), 'Controller was not successful!');
-        $this->assertEquals($read, !$client->getResponse()->isForbidden(), 'Permission Checking not working!');
+        $this->assertSame($read, $client->getResponse()->isSuccessful(), 'Controller was not successful!');
+        $this->assertSame($read, ! $client->getResponse()->isForbidden(), 'Permission Checking not working!');
     }
 
     /**
@@ -76,7 +79,7 @@ abstract class AbstractAdminControllerTest extends WebTestCase
      * @group slow
      * Tests if it possible to access an specific entity. Checks if permissions are working.
      */
-    public function testReadEntity(string $user, bool $read)
+    public function testReadEntity(string $user, bool $read): void
     {
         //Test read access
         $client = static::createClient([], [
@@ -85,15 +88,15 @@ abstract class AbstractAdminControllerTest extends WebTestCase
         ]);
 
         $client->catchExceptions(false);
-        if (false == $read) {
+        if (false === $read) {
             $this->expectException(AccessDeniedException::class);
         }
 
         //Test read/list access by access /new overview page
         $crawler = $client->request('GET', static::$base_path.'/1');
         $this->assertFalse($client->getResponse()->isRedirect());
-        $this->assertEquals($read, $client->getResponse()->isSuccessful(), 'Controller was not successful!');
-        $this->assertEquals($read, !$client->getResponse()->isForbidden(), 'Permission Checking not working!');
+        $this->assertSame($read, $client->getResponse()->isSuccessful(), 'Controller was not successful!');
+        $this->assertSame($read, ! $client->getResponse()->isForbidden(), 'Permission Checking not working!');
     }
 
     public function deleteDataProvider()
@@ -112,7 +115,7 @@ abstract class AbstractAdminControllerTest extends WebTestCase
      * @group slow
      * @dataProvider deleteDataProvider
      */
-    public function testDeleteEntity(string $user, bool $delete)
+    public function testDeleteEntity(string $user, bool $delete): void
     {
         //Test read access
         $client = static::createClient([], [
@@ -121,7 +124,7 @@ abstract class AbstractAdminControllerTest extends WebTestCase
         ]);
 
         $client->catchExceptions(false);
-        if (false == $delete) {
+        if (false === $delete) {
             $this->expectException(AccessDeniedException::class);
         }
 
@@ -129,7 +132,7 @@ abstract class AbstractAdminControllerTest extends WebTestCase
         $crawler = $client->request('DELETE', static::$base_path.'/7');
 
         //Page is redirected to '/new', when delete was successful
-        $this->assertEquals($delete, $client->getResponse()->isRedirect(static::$base_path.'/new'));
-        $this->assertEquals($delete, !$client->getResponse()->isForbidden(), 'Permission Checking not working!');
+        $this->assertSame($delete, $client->getResponse()->isRedirect(static::$base_path.'/new'));
+        $this->assertSame($delete, ! $client->getResponse()->isForbidden(), 'Permission Checking not working!');
     }
 }
diff --git a/tests/Controller/AdminPages/AttachmentTypeControllerTest.php b/tests/Controller/AdminPages/AttachmentTypeControllerTest.php
index 952211a6..8739c475 100644
--- a/tests/Controller/AdminPages/AttachmentTypeControllerTest.php
+++ b/tests/Controller/AdminPages/AttachmentTypeControllerTest.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).
  *
diff --git a/tests/Controller/AdminPages/CategoryControllerTest.php b/tests/Controller/AdminPages/CategoryControllerTest.php
index 12460519..5f1c9666 100644
--- a/tests/Controller/AdminPages/CategoryControllerTest.php
+++ b/tests/Controller/AdminPages/CategoryControllerTest.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).
  *
diff --git a/tests/Controller/AdminPages/DeviceControllerTest.php b/tests/Controller/AdminPages/DeviceControllerTest.php
index d7fa1ab0..939b8c5f 100644
--- a/tests/Controller/AdminPages/DeviceControllerTest.php
+++ b/tests/Controller/AdminPages/DeviceControllerTest.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).
  *
diff --git a/tests/Controller/AdminPages/FootprintControllerTest.php b/tests/Controller/AdminPages/FootprintControllerTest.php
index 10c3bbc2..441ae2ce 100644
--- a/tests/Controller/AdminPages/FootprintControllerTest.php
+++ b/tests/Controller/AdminPages/FootprintControllerTest.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).
  *
diff --git a/tests/Controller/AdminPages/ManufacturerControllerTest.php b/tests/Controller/AdminPages/ManufacturerControllerTest.php
index 7c9151a3..7171fc06 100644
--- a/tests/Controller/AdminPages/ManufacturerControllerTest.php
+++ b/tests/Controller/AdminPages/ManufacturerControllerTest.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).
  *
diff --git a/tests/Controller/AdminPages/MeasurementUnitControllerTest.php b/tests/Controller/AdminPages/MeasurementUnitControllerTest.php
index 090ca2f3..43a7cf3b 100644
--- a/tests/Controller/AdminPages/MeasurementUnitControllerTest.php
+++ b/tests/Controller/AdminPages/MeasurementUnitControllerTest.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).
  *
diff --git a/tests/Controller/AdminPages/StorelocationControllerTest.php b/tests/Controller/AdminPages/StorelocationControllerTest.php
index e1bd0e9f..67172371 100644
--- a/tests/Controller/AdminPages/StorelocationControllerTest.php
+++ b/tests/Controller/AdminPages/StorelocationControllerTest.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).
  *
diff --git a/tests/Controller/AdminPages/SupplierControllerTest.php b/tests/Controller/AdminPages/SupplierControllerTest.php
index 31559c42..9705d231 100644
--- a/tests/Controller/AdminPages/SupplierControllerTest.php
+++ b/tests/Controller/AdminPages/SupplierControllerTest.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).
  *
diff --git a/tests/Controller/RedirectControllerTest.php b/tests/Controller/RedirectControllerTest.php
index da024a64..6c31509a 100644
--- a/tests/Controller/RedirectControllerTest.php
+++ b/tests/Controller/RedirectControllerTest.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).
  *
@@ -35,7 +38,7 @@ class RedirectControllerTest extends WebTestCase
     protected $userRepo;
     protected $client;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $this->client = static::createClient([], [
             'PHP_AUTH_USER' => 'user',
@@ -66,15 +69,15 @@ class RedirectControllerTest extends WebTestCase
      * @dataProvider urlMatchDataProvider
      * @group slow
      */
-    public function testUrlMatch($url, $expect_redirect)
+    public function testUrlMatch($url, $expect_redirect): void
     {
         //$client = static::createClient();
         $this->client->request('GET', $url);
         $response = $this->client->getResponse();
         if ($expect_redirect) {
-            $this->assertEquals(302, $response->getStatusCode());
+            $this->assertSame(302, $response->getStatusCode());
         }
-        $this->assertEquals($expect_redirect, $response->isRedirect());
+        $this->assertSame($expect_redirect, $response->isRedirect());
     }
 
     public function urlAddLocaleDataProvider()
@@ -103,7 +106,7 @@ class RedirectControllerTest extends WebTestCase
      * @param $input_path
      * @param $redirect_path
      */
-    public function testAddLocale($user_locale, $input_path, $redirect_path)
+    public function testAddLocale($user_locale, $input_path, $redirect_path): void
     {
         //Redirect path is absolute
         $redirect_path = 'http://localhost'.$redirect_path;
@@ -116,6 +119,6 @@ class RedirectControllerTest extends WebTestCase
 
         $this->client->followRedirects(false);
         $this->client->request('GET', $input_path);
-        $this->assertEquals($redirect_path, $this->client->getResponse()->headers->get('Location'));
+        $this->assertSame($redirect_path, $this->client->getResponse()->headers->get('Location'));
     }
 }
diff --git a/tests/Entity/Attachments/AttachmentTest.php b/tests/Entity/Attachments/AttachmentTest.php
index b39e1f62..1fd2ec98 100644
--- a/tests/Entity/Attachments/AttachmentTest.php
+++ b/tests/Entity/Attachments/AttachmentTest.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).
  *
@@ -99,7 +102,7 @@ class AttachmentTest extends TestCase
 
         //This must not throw an exception
         $attachment->setElement($element);
-        $this->assertEquals($element, $attachment->getElement());
+        $this->assertSame($element, $attachment->getElement());
     }
 
     /**
@@ -141,11 +144,11 @@ class AttachmentTest extends TestCase
     /**
      * @dataProvider externalDataProvider
      */
-    public function testIsExternal($path, $expected)
+    public function testIsExternal($path, $expected): void
     {
         $attachment = new PartAttachment();
         $this->setProtectedProperty($attachment, 'path', $path);
-        $this->assertEquals($expected, $attachment->isExternal());
+        $this->assertSame($expected, $attachment->isExternal());
     }
 
     public function extensionDataProvider()
@@ -167,12 +170,12 @@ class AttachmentTest extends TestCase
     /**
      * @dataProvider extensionDataProvider
      */
-    public function testGetExtension($path, $originalFilename, $expected)
+    public function testGetExtension($path, $originalFilename, $expected): void
     {
         $attachment = new PartAttachment();
         $this->setProtectedProperty($attachment, 'path', $path);
         $this->setProtectedProperty($attachment, 'original_filename', $originalFilename);
-        $this->assertEquals($expected, $attachment->getExtension());
+        $this->assertSame($expected, $attachment->getExtension());
     }
 
     public function pictureDataProvider()
@@ -192,11 +195,11 @@ class AttachmentTest extends TestCase
     /**
      * @dataProvider pictureDataProvider
      */
-    public function testIsPicture($path, $expected)
+    public function testIsPicture($path, $expected): void
     {
         $attachment = new PartAttachment();
         $this->setProtectedProperty($attachment, 'path', $path);
-        $this->assertEquals($expected, $attachment->isPicture());
+        $this->assertSame($expected, $attachment->isPicture());
     }
 
     public function builtinDataProvider()
@@ -214,11 +217,11 @@ class AttachmentTest extends TestCase
     /**
      * @dataProvider builtinDataProvider
      */
-    public function testIsBuiltIn($path, $expected)
+    public function testIsBuiltIn($path, $expected): void
     {
         $attachment = new PartAttachment();
         $this->setProtectedProperty($attachment, 'path', $path);
-        $this->assertEquals($expected, $attachment->isBuiltIn());
+        $this->assertSame($expected, $attachment->isBuiltIn());
     }
 
     public function hostDataProvider()
@@ -233,11 +236,11 @@ class AttachmentTest extends TestCase
     /**
      * @dataProvider hostDataProvider
      */
-    public function testGetHost($path, $expected)
+    public function testGetHost($path, $expected): void
     {
         $attachment = new PartAttachment();
         $this->setProtectedProperty($attachment, 'path', $path);
-        $this->assertEquals($expected, $attachment->getHost());
+        $this->assertSame($expected, $attachment->getHost());
     }
 
     public function filenameProvider()
@@ -252,15 +255,15 @@ class AttachmentTest extends TestCase
     /**
      * @dataProvider filenameProvider
      */
-    public function testGetFilename($path, $original_filename, $expected)
+    public function testGetFilename($path, $original_filename, $expected): void
     {
         $attachment = new PartAttachment();
         $this->setProtectedProperty($attachment, 'path', $path);
         $this->setProtectedProperty($attachment, 'original_filename', $original_filename);
-        $this->assertEquals($expected, $attachment->getFilename());
+        $this->assertSame($expected, $attachment->getFilename());
     }
 
-    public function testIsURL()
+    public function testIsURL(): void
     {
         $url = '%MEDIA%/test.txt';
         $this->assertFalse(Attachment::isURL($url));
@@ -279,10 +282,8 @@ class AttachmentTest extends TestCase
      * @param object $object   - instance in which protected value is being modified
      * @param string $property - property on instance being modified
      * @param mixed  $value    - new value of the property being modified
-     *
-     * @return void
      */
-    public function setProtectedProperty($object, $property, $value)
+    public function setProtectedProperty($object, $property, $value): void
     {
         $reflection = new ReflectionClass($object);
         $reflection_property = $reflection->getProperty($property);
diff --git a/tests/Entity/Attachments/AttachmentTypeTest.php b/tests/Entity/Attachments/AttachmentTypeTest.php
index 1754cb3f..13911ced 100644
--- a/tests/Entity/Attachments/AttachmentTypeTest.php
+++ b/tests/Entity/Attachments/AttachmentTypeTest.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).
  *
@@ -27,7 +30,7 @@ use PHPUnit\Framework\TestCase;
 
 class AttachmentTypeTest extends TestCase
 {
-    public function testEmptyState()
+    public function testEmptyState(): void
     {
         $attachment_type = new AttachmentType();
         $this->assertInstanceOf(Collection::class, $attachment_type->getAttachmentsForType());
diff --git a/tests/Entity/Parts/PartLotTest.php b/tests/Entity/Parts/PartLotTest.php
index 84fe5f62..d5ed40c8 100644
--- a/tests/Entity/Parts/PartLotTest.php
+++ b/tests/Entity/Parts/PartLotTest.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).
  *
@@ -26,7 +29,7 @@ use PHPUnit\Framework\TestCase;
 
 class PartLotTest extends TestCase
 {
-    public function testIsExpired()
+    public function testIsExpired(): void
     {
         $lot = new PartLot();
         $this->assertNull($lot->isExpired(), 'Lot must be return null when no Expiration date is set!');
diff --git a/tests/Entity/Parts/PartTest.php b/tests/Entity/Parts/PartTest.php
index 6842ee3b..c3f7d1cf 100644
--- a/tests/Entity/Parts/PartTest.php
+++ b/tests/Entity/Parts/PartTest.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).
  *
@@ -29,7 +32,7 @@ use PHPUnit\Framework\TestCase;
 
 class PartTest extends TestCase
 {
-    public function testAddRemovePartLot()
+    public function testAddRemovePartLot(): void
     {
         $part = new Part();
         $this->assertInstanceOf(Collection::class, $part->getPartLots());
@@ -38,33 +41,33 @@ class PartTest extends TestCase
         //Add element
         $lot = new PartLot();
         $part->addPartLot($lot);
-        $this->assertEquals($part, $lot->getPart());
-        $this->assertEquals(1, $part->getPartLots()->count());
+        $this->assertSame($part, $lot->getPart());
+        $this->assertSame(1, $part->getPartLots()->count());
 
         //Remove element
         $part->removePartLot($lot);
         $this->assertTrue($part->getPartLots()->isEmpty());
     }
 
-    public function testGetSetMinamount()
+    public function testGetSetMinamount(): void
     {
         $part = new Part();
         $measurement_unit = new MeasurementUnit();
 
         //Without an set measurement unit the part must return an int
         $part->setMinAmount(1.345);
-        $this->assertEquals(1, $part->getMinAmount());
+        $this->assertSame(1.0, $part->getMinAmount());
 
         //If an non int-based unit is assigned, an float is returned
         $part->setPartUnit($measurement_unit);
-        $this->assertEquals(1.345, $part->getMinAmount());
+        $this->assertSame(1.345, $part->getMinAmount());
 
         //If an int-based unit is assigned an int is returned
         $measurement_unit->setIsInteger(true);
-        $this->assertEquals(1, $part->getMinAmount());
+        $this->assertSame(1.0, $part->getMinAmount());
     }
 
-    public function testUseFloatAmount()
+    public function testUseFloatAmount(): void
     {
         $part = new Part();
         $measurement_unit = new MeasurementUnit();
@@ -79,13 +82,13 @@ class PartTest extends TestCase
         $this->assertFalse($part->useFloatAmount());
     }
 
-    public function testGetAmountSum()
+    public function testGetAmountSum(): void
     {
         $part = new Part();
         $measurement_unit = new MeasurementUnit();
         $datetime = new \DateTime();
 
-        $this->assertEquals(0, $part->getAmountSum());
+        $this->assertSame(0.0, $part->getAmountSum());
 
         $part->addPartLot((new PartLot())->setAmount(3.141));
         $part->addPartLot((new PartLot())->setAmount(10.0));
@@ -96,15 +99,15 @@ class PartTest extends TestCase
                 ->setExpirationDate($datetime->setTimestamp(strtotime('now -1 hour')))
         );
 
-        $this->assertEquals(13, $part->getAmountSum());
+        $this->assertSame(13.0, $part->getAmountSum());
 
         $part->setPartUnit($measurement_unit);
-        $this->assertEquals(13.141, $part->getAmountSum());
+        $this->assertSame(13.141, $part->getAmountSum());
 
         //1 billion part lot
         $part->addPartLot((new PartLot())->setAmount(1000000000));
-        $this->assertEquals(1000000013.141, $part->getAmountSum());
+        $this->assertSame(1000000013.141, $part->getAmountSum());
         $measurement_unit->setIsInteger(true);
-        $this->assertEquals(1000000013, $part->getAmountSum());
+        $this->assertSame(1000000013.0, $part->getAmountSum());
     }
 }
diff --git a/tests/Entity/PriceSystem/CurrencyTest.php b/tests/Entity/PriceSystem/CurrencyTest.php
index 46540581..81b65c60 100644
--- a/tests/Entity/PriceSystem/CurrencyTest.php
+++ b/tests/Entity/PriceSystem/CurrencyTest.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).
  *
@@ -26,7 +29,7 @@ use PHPUnit\Framework\TestCase;
 
 class CurrencyTest extends TestCase
 {
-    public function testGetInverseExchangeRate()
+    public function testGetInverseExchangeRate(): void
     {
         $currency = new Currency();
 
@@ -37,6 +40,6 @@ class CurrencyTest extends TestCase
         $this->assertNull($currency->getInverseExchangeRate());
 
         $currency->setExchangeRate('1.45643');
-        $this->assertEquals('0.68661', $currency->getInverseExchangeRate());
+        $this->assertSame('0.68661', $currency->getInverseExchangeRate());
     }
 }
diff --git a/tests/Entity/PriceSystem/OrderdetailTest.php b/tests/Entity/PriceSystem/OrderdetailTest.php
index d9ae8666..0e46553a 100644
--- a/tests/Entity/PriceSystem/OrderdetailTest.php
+++ b/tests/Entity/PriceSystem/OrderdetailTest.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 +31,7 @@ use PHPUnit\Framework\TestCase;
 
 class OrderdetailTest extends TestCase
 {
-    public function testAddRemovePricdetails()
+    public function testAddRemovePricdetails(): void
     {
         $orderdetail = new Orderdetail();
         $this->assertInstanceOf(Collection::class, $orderdetail->getPricedetails());
@@ -36,15 +39,15 @@ class OrderdetailTest extends TestCase
 
         $pricedetail = new Pricedetail();
         $orderdetail->addPricedetail($pricedetail);
-        $this->assertEquals($orderdetail, $pricedetail->getOrderdetail());
-        $this->assertEquals(1, $orderdetail->getPricedetails()->count());
+        $this->assertSame($orderdetail, $pricedetail->getOrderdetail());
+        $this->assertSame(1, $orderdetail->getPricedetails()->count());
 
         //After removal of the pricedetail, the orderdetail must be empty again
         $orderdetail->removePricedetail($pricedetail);
         $this->assertTrue($orderdetail->getPricedetails()->isEmpty());
     }
 
-    public function testFindPriceForQty()
+    public function testFindPriceForQty(): void
     {
         $price0 = (new Pricedetail())->setMinDiscountQuantity(0.23);
         $price1 = (new Pricedetail())->setMinDiscountQuantity(1);
@@ -54,10 +57,10 @@ class OrderdetailTest extends TestCase
         $this->assertNull($orderdetail->findPriceForQty(0));
         $this->assertNull($orderdetail->findPriceForQty(0.1));
 
-        $this->assertEquals($price0, $orderdetail->findPriceForQty(0.5));
-        $this->assertEquals($price1, $orderdetail->findPriceForQty(1));
-        $this->assertEquals($price1, $orderdetail->findPriceForQty(1.5));
-        $this->assertEquals($price5, $orderdetail->findPriceForQty(5.3));
-        $this->assertEquals($price5, $orderdetail->findPriceForQty(10000));
+        $this->assertSame($price0, $orderdetail->findPriceForQty(0.5));
+        $this->assertSame($price1, $orderdetail->findPriceForQty(1));
+        $this->assertSame($price1, $orderdetail->findPriceForQty(1.5));
+        $this->assertSame($price5, $orderdetail->findPriceForQty(5.3));
+        $this->assertSame($price5, $orderdetail->findPriceForQty(10000));
     }
 }
diff --git a/tests/Entity/PriceSystem/PricedetailTest.php b/tests/Entity/PriceSystem/PricedetailTest.php
index 860fc48a..954448fe 100644
--- a/tests/Entity/PriceSystem/PricedetailTest.php
+++ b/tests/Entity/PriceSystem/PricedetailTest.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).
  *
@@ -28,23 +31,23 @@ use PHPUnit\Framework\TestCase;
 
 class PricedetailTest extends TestCase
 {
-    public function testGetPricePerUnit()
+    public function testGetPricePerUnit(): void
     {
         $pricedetail = new Pricedetail();
         $pricedetail->setPrice('100.234');
 
-        $this->assertEquals('100.23400', $pricedetail->getPricePerUnit());
+        $this->assertSame('100.23400', $pricedetail->getPricePerUnit());
 
-        $pricedetail->setPriceRelatedQuantity('2.3');
-        $this->assertEquals('43.58000', $pricedetail->getPricePerUnit());
-        $this->assertEquals('139.45600', $pricedetail->getPricePerUnit('3.2'));
+        $pricedetail->setPriceRelatedQuantity(2.3);
+        $this->assertSame('43.58000', $pricedetail->getPricePerUnit());
+        $this->assertSame('139.45600', $pricedetail->getPricePerUnit('3.2'));
 
         $pricedetail->setPrice('10000000.2345'); //Ten million
         $pricedetail->setPriceRelatedQuantity(1.234e9); //100 billion
-        $this->assertEquals('0.00810', $pricedetail->getPricePerUnit());
+        $this->assertSame('0.00810', $pricedetail->getPricePerUnit());
     }
 
-    public function testGetPriceRelatedQuantity()
+    public function testGetPriceRelatedQuantity(): void
     {
         $pricedetail = new Pricedetail();
         $part = $this->createMock(Part::class);
@@ -58,21 +61,21 @@ class PricedetailTest extends TestCase
         $orderdetail2->method('getPart')->willReturn($part2);
 
         //By default a price detail returns 1
-        $this->assertEquals(1, $pricedetail->getPriceRelatedQuantity());
+        $this->assertSame(1.0, $pricedetail->getPriceRelatedQuantity());
 
         $pricedetail->setOrderdetail($orderdetail);
         $pricedetail->setPriceRelatedQuantity(10.23);
-        $this->assertEquals(10, $pricedetail->getPriceRelatedQuantity());
+        $this->assertSame(10.0, $pricedetail->getPriceRelatedQuantity());
         //Price related quantity must not be zero!
         $pricedetail->setPriceRelatedQuantity(0.23);
-        $this->assertEquals(1, $pricedetail->getPriceRelatedQuantity());
+        $this->assertSame(1.0, $pricedetail->getPriceRelatedQuantity());
 
         //With an part that has an float amount unit, also values like 0.23 can be returned
         $pricedetail->setOrderdetail($orderdetail2);
-        $this->assertEquals(0.23, $pricedetail->getPriceRelatedQuantity());
+        $this->assertSame(0.23, $pricedetail->getPriceRelatedQuantity());
     }
 
-    public function testGetMinDiscountQuantity()
+    public function testGetMinDiscountQuantity(): void
     {
         $pricedetail = new Pricedetail();
         $part = $this->createMock(Part::class);
@@ -86,17 +89,17 @@ class PricedetailTest extends TestCase
         $orderdetail2->method('getPart')->willReturn($part2);
 
         //By default a price detail returns 1
-        $this->assertEquals(1, $pricedetail->getMinDiscountQuantity());
+        $this->assertSame(1.0, $pricedetail->getMinDiscountQuantity());
 
         $pricedetail->setOrderdetail($orderdetail);
         $pricedetail->setMinDiscountQuantity(10.23);
-        $this->assertEquals(10, $pricedetail->getMinDiscountQuantity());
+        $this->assertSame(10.0, $pricedetail->getMinDiscountQuantity());
         //Price related quantity must not be zero!
         $pricedetail->setMinDiscountQuantity(0.23);
-        $this->assertEquals(1, $pricedetail->getMinDiscountQuantity());
+        $this->assertSame(1.0, $pricedetail->getMinDiscountQuantity());
 
         //With an part that has an float amount unit, also values like 0.23 can be returned
         $pricedetail->setOrderdetail($orderdetail2);
-        $this->assertEquals(0.23, $pricedetail->getMinDiscountQuantity());
+        $this->assertSame(0.23, $pricedetail->getMinDiscountQuantity());
     }
 }
diff --git a/tests/Entity/StructuralDBElementTest.php b/tests/Entity/StructuralDBElementTest.php
index bc431627..3125e3c9 100644
--- a/tests/Entity/StructuralDBElementTest.php
+++ b/tests/Entity/StructuralDBElementTest.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).
  *
@@ -39,7 +42,7 @@ class StructuralDBElementTest extends TestCase
     protected $child1_1;
     protected $child1_2;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp(); // TODO: Change the autogenerated stub
 
@@ -58,14 +61,14 @@ class StructuralDBElementTest extends TestCase
         $this->child1_2->setName('child1_2')->setParent($this->child1);
     }
 
-    public function testIsRoot()
+    public function testIsRoot(): void
     {
         $this->assertTrue($this->root->isRoot());
         $this->assertFalse($this->child1->isRoot());
         $this->assertFalse($this->child1_2->isRoot());
     }
 
-    public function testIsChildOf()
+    public function testIsChildOf(): void
     {
         //Root must not be the child of any other node
         $this->assertFalse($this->root->isChildOf($this->child1));
@@ -79,14 +82,14 @@ class StructuralDBElementTest extends TestCase
         $this->assertTrue($this->child1_2->isChildOf($this->root));
     }
 
-    public function testChildOfDifferentClasses()
+    public function testChildOfDifferentClasses(): void
     {
         $this->expectException(\InvalidArgumentException::class);
         $category = new Category();
         $this->root->isChildOf($category);
     }
 
-    public function testChildOfExtendedClass()
+    public function testChildOfExtendedClass(): void
     {
         //Doctrine extends the entities for proxy classes so the isChildOf mus also work for inheritance types
         $inheritance = new class() extends AttachmentType {
@@ -96,25 +99,25 @@ class StructuralDBElementTest extends TestCase
         $this->assertFalse($this->root->isChildOf($inheritance));
     }
 
-    public function testGetLevel()
+    public function testGetLevel(): void
     {
-        $this->assertEquals(0, $this->root->getLevel());
-        $this->assertEquals(1, $this->child1->getLevel());
+        $this->assertSame(0, $this->root->getLevel());
+        $this->assertSame(1, $this->child1->getLevel());
         $this->assertSame(1, $this->child2->getLevel());
         $this->assertSame(2, $this->child1_2->getLevel());
         $this->assertSame(2, $this->child1_1->getLevel());
     }
 
-    public function testGetFullPath()
+    public function testGetFullPath(): void
     {
         $this->assertSame('root/child1/child1_1', $this->child1_1->getFullPath('/'));
         $this->assertSame('root#child2', $this->child2->getFullPath('#'));
     }
 
-    public function testGetPathArray()
+    public function testGetPathArray(): void
     {
-        $this->assertEquals([$this->root, $this->child1, $this->child1_1], $this->child1_1->getPathArray());
-        $this->assertEquals([$this->root, $this->child1], $this->child1->getPathArray());
-        $this->assertEquals([$this->root], $this->root->getPathArray());
+        $this->assertSame([$this->root, $this->child1, $this->child1_1], $this->child1_1->getPathArray());
+        $this->assertSame([$this->root, $this->child1], $this->child1->getPathArray());
+        $this->assertSame([$this->root], $this->root->getPathArray());
     }
 }
diff --git a/tests/Entity/UserSystem/PermissionsEmbedTest.php b/tests/Entity/UserSystem/PermissionsEmbedTest.php
index ef7c7be7..fa7b308d 100644
--- a/tests/Entity/UserSystem/PermissionsEmbedTest.php
+++ b/tests/Entity/UserSystem/PermissionsEmbedTest.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).
  *
@@ -27,7 +30,7 @@ use PHPUnit\Framework\TestCase;
 
 class PermissionsEmbedTest extends TestCase
 {
-    public function testGetPermissionValue()
+    public function testGetPermissionValue(): void
     {
         $embed = new PermissionsEmbed();
         //For newly created embedded, all things should be set to inherit => null
@@ -71,7 +74,7 @@ class PermissionsEmbedTest extends TestCase
         $this->assertNull($embed->getPermissionValue(PermissionsEmbed::PARTS, 6));
     }
 
-    public function testGetBitValue()
+    public function testGetBitValue(): void
     {
         $embed = new PermissionsEmbed();
 
@@ -83,14 +86,14 @@ class PermissionsEmbedTest extends TestCase
         $property->setValue($embed, 0b11011000); // 11 01 10 00
 
         //Test if function is working correctly
-        $this->assertEquals(PermissionsEmbed::INHERIT, $embed->getBitValue(PermissionsEmbed::PARTS, 0));
-        $this->assertEquals(PermissionsEmbed::DISALLOW, $embed->getBitValue(PermissionsEmbed::PARTS, 2));
-        $this->assertEquals(PermissionsEmbed::ALLOW, $embed->getBitValue(PermissionsEmbed::PARTS, 4));
+        $this->assertSame(PermissionsEmbed::INHERIT, $embed->getBitValue(PermissionsEmbed::PARTS, 0));
+        $this->assertSame(PermissionsEmbed::DISALLOW, $embed->getBitValue(PermissionsEmbed::PARTS, 2));
+        $this->assertSame(PermissionsEmbed::ALLOW, $embed->getBitValue(PermissionsEmbed::PARTS, 4));
         // 11 is reserved, but it should be also treat as INHERIT.
-        $this->assertEquals(0b11, $embed->getBitValue(PermissionsEmbed::PARTS, 6));
+        $this->assertSame(0b11, $embed->getBitValue(PermissionsEmbed::PARTS, 6));
     }
 
-    public function testInvalidPermissionName()
+    public function testInvalidPermissionName(): void
     {
         $embed = new PermissionsEmbed();
         //When encoutering an unknown permission name the class must throw an exception
@@ -98,7 +101,7 @@ class PermissionsEmbedTest extends TestCase
         $embed->getPermissionValue('invalid', 0);
     }
 
-    public function testInvalidBit1()
+    public function testInvalidBit1(): void
     {
         $embed = new PermissionsEmbed();
         //When encoutering an negative bit the class must throw an exception
@@ -106,7 +109,7 @@ class PermissionsEmbedTest extends TestCase
         $embed->getPermissionValue('parts', -1);
     }
 
-    public function testInvalidBit2()
+    public function testInvalidBit2(): void
     {
         $embed = new PermissionsEmbed();
         //When encoutering an odd bit number it must throw an error.
@@ -114,7 +117,7 @@ class PermissionsEmbedTest extends TestCase
         $embed->getPermissionValue('parts', 1);
     }
 
-    public function testInvalidBit3()
+    public function testInvalidBit3(): void
     {
         $embed = new PermissionsEmbed();
         //When encoutering an too high bit number it must throw an error.
@@ -145,33 +148,33 @@ class PermissionsEmbedTest extends TestCase
     /**
      * @dataProvider getStatesBINARY
      */
-    public function testsetBitValue($value)
+    public function testTestsetBitValue($value): void
     {
         $embed = new PermissionsEmbed();
         //Check if it returns itself, for chaining.
-        $this->assertEquals($embed, $embed->setBitValue(PermissionsEmbed::PARTS, 0, $value));
-        $this->assertEquals($value, $embed->getBitValue(PermissionsEmbed::PARTS, 0));
+        $this->assertSame($embed, $embed->setBitValue(PermissionsEmbed::PARTS, 0, $value));
+        $this->assertSame($value, $embed->getBitValue(PermissionsEmbed::PARTS, 0));
     }
 
     /**
      * @dataProvider getStatesBOOL
      */
-    public function testSetPermissionValue($value)
+    public function testSetPermissionValue($value): void
     {
         $embed = new PermissionsEmbed();
         //Check if it returns itself, for chaining.
-        $this->assertEquals($embed, $embed->setPermissionValue(PermissionsEmbed::PARTS, 0, $value));
-        $this->assertEquals($value, $embed->getPermissionValue(PermissionsEmbed::PARTS, 0));
+        $this->assertSame($embed, $embed->setPermissionValue(PermissionsEmbed::PARTS, 0, $value));
+        $this->assertSame($value, $embed->getPermissionValue(PermissionsEmbed::PARTS, 0));
     }
 
-    public function testSetRawPermissionValue()
+    public function testSetRawPermissionValue(): void
     {
         $embed = new PermissionsEmbed();
         $embed->setRawPermissionValue(PermissionsEmbed::PARTS, 10);
-        $this->assertEquals(10, $embed->getRawPermissionValue(PermissionsEmbed::PARTS));
+        $this->assertSame(10, $embed->getRawPermissionValue(PermissionsEmbed::PARTS));
     }
 
-    public function testSetRawPermissionValues()
+    public function testSetRawPermissionValues(): void
     {
         $embed = new PermissionsEmbed();
         $embed->setRawPermissionValues([
@@ -180,9 +183,9 @@ class PermissionsEmbedTest extends TestCase
             PermissionsEmbed::CATEGORIES => 1304,
         ]);
 
-        $this->assertEquals(0, $embed->getRawPermissionValue(PermissionsEmbed::PARTS));
-        $this->assertEquals(100, $embed->getRawPermissionValue(PermissionsEmbed::USERS));
-        $this->assertEquals(1304, $embed->getRawPermissionValue(PermissionsEmbed::CATEGORIES));
+        $this->assertSame(0, $embed->getRawPermissionValue(PermissionsEmbed::PARTS));
+        $this->assertSame(100, $embed->getRawPermissionValue(PermissionsEmbed::USERS));
+        $this->assertSame(1304, $embed->getRawPermissionValue(PermissionsEmbed::CATEGORIES));
 
         //Test second method to pass perm names and values
         $embed->setRawPermissionValues(
@@ -190,8 +193,8 @@ class PermissionsEmbedTest extends TestCase
             [0, 100, 1304]
         );
 
-        $this->assertEquals(0, $embed->getRawPermissionValue(PermissionsEmbed::PARTS));
-        $this->assertEquals(100, $embed->getRawPermissionValue(PermissionsEmbed::USERS));
-        $this->assertEquals(1304, $embed->getRawPermissionValue(PermissionsEmbed::CATEGORIES));
+        $this->assertSame(0, $embed->getRawPermissionValue(PermissionsEmbed::PARTS));
+        $this->assertSame(100, $embed->getRawPermissionValue(PermissionsEmbed::USERS));
+        $this->assertSame(1304, $embed->getRawPermissionValue(PermissionsEmbed::CATEGORIES));
     }
 }
diff --git a/tests/Entity/UserSystem/UserTest.php b/tests/Entity/UserSystem/UserTest.php
index 6a4a43ff..e82f2840 100644
--- a/tests/Entity/UserSystem/UserTest.php
+++ b/tests/Entity/UserSystem/UserTest.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).
  *
@@ -27,15 +30,15 @@ use PHPUnit\Framework\TestCase;
 
 class UserTest extends TestCase
 {
-    public function testGetFullName()
+    public function testGetFullName(): void
     {
         $user = new User();
         $user->setName('username');
         $user->setFirstName('John');
         $user->setLastName('Doe');
 
-        $this->assertEquals('John Doe', $user->getFullName(false));
-        $this->assertEquals('John Doe (username)', $user->getFullName(true));
+        $this->assertSame('John Doe', $user->getFullName(false));
+        $this->assertSame('John Doe (username)', $user->getFullName(true));
     }
 
     public function googleAuthenticatorEnabledDataProvider(): array
@@ -50,7 +53,7 @@ class UserTest extends TestCase
     /**
      * @dataProvider googleAuthenticatorEnabledDataProvider
      */
-    public function testIsGoogleAuthenticatorEnabled(?string $secret, bool $expected)
+    public function testIsGoogleAuthenticatorEnabled(?string $secret, bool $expected): void
     {
         $user = new User();
         $user->setGoogleAuthenticatorSecret($secret);
@@ -60,14 +63,14 @@ class UserTest extends TestCase
     /**
      * @requires PHPUnit 8
      */
-    public function testSetBackupCodes()
+    public function testSetBackupCodes(): void
     {
         $user = new User();
         $codes = ['test', 'invalid', 'test'];
         $user->setBackupCodes($codes);
         // Backup Codes generation date must be changed!
         $this->assertEqualsWithDelta(new \DateTime(), $user->getBackupCodesGenerationDate(), 0.1);
-        $this->assertEquals($codes, $user->getBackupCodes());
+        $this->assertSame($codes, $user->getBackupCodes());
 
         //Test what happens if we delete the backup keys
         $user->setBackupCodes([]);
@@ -75,7 +78,7 @@ class UserTest extends TestCase
         $this->assertNull($user->getBackupCodesGenerationDate());
     }
 
-    public function testIsBackupCode()
+    public function testIsBackupCode(): void
     {
         $user = new User();
         $codes = ['aaaa', 'bbbb', 'cccc', 'dddd'];
@@ -88,7 +91,7 @@ class UserTest extends TestCase
         $this->assertFalse($user->isBackupCode('zzzz'));
     }
 
-    public function testInvalidateBackupCode()
+    public function testInvalidateBackupCode(): void
     {
         $user = new User();
         $codes = ['aaaa', 'bbbb', 'cccc', 'dddd'];
@@ -106,7 +109,7 @@ class UserTest extends TestCase
         $user->invalidateBackupCode('zzzz');
     }
 
-    public function testInvalidateTrustedDeviceTokens()
+    public function testInvalidateTrustedDeviceTokens(): void
     {
         $user = new User();
         $old_value = $user->getTrustedTokenVersion();
@@ -115,7 +118,7 @@ class UserTest extends TestCase
         $this->assertGreaterThan($old_value, $user->getTrustedTokenVersion());
     }
 
-    public function testIsU2fEnabled()
+    public function testIsU2fEnabled(): void
     {
         $user = new User();
         $user->addU2FKey(new U2FKey());
diff --git a/tests/EventSubscriber/PasswordChangeNeededSubscriberTest.php b/tests/EventSubscriber/PasswordChangeNeededSubscriberTest.php
index f152f617..e1e15199 100644
--- a/tests/EventSubscriber/PasswordChangeNeededSubscriberTest.php
+++ b/tests/EventSubscriber/PasswordChangeNeededSubscriberTest.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).
  *
@@ -29,7 +32,7 @@ use PHPUnit\Framework\TestCase;
 
 class PasswordChangeNeededSubscriberTest extends TestCase
 {
-    public function testTFARedirectNeeded()
+    public function testTFARedirectNeeded(): void
     {
         $user = new User();
         $group = new Group();
diff --git a/tests/Helpers/BBCodeToMarkdownConverterTest.php b/tests/Helpers/BBCodeToMarkdownConverterTest.php
index 500ce97c..9c79a7db 100644
--- a/tests/Helpers/BBCodeToMarkdownConverterTest.php
+++ b/tests/Helpers/BBCodeToMarkdownConverterTest.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 +31,7 @@ class BBCodeToMarkdownConverterTest extends TestCase
 {
     protected $converter;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $this->converter = new BBCodeToMarkdownConverter();
     }
@@ -52,8 +55,8 @@ class BBCodeToMarkdownConverterTest extends TestCase
      * @param $bbcode
      * @param $expected
      */
-    public function testConvert($bbcode, $expected)
+    public function testConvert($bbcode, $expected): void
     {
-        $this->assertEquals($expected, $this->converter->convert($bbcode));
+        $this->assertSame($expected, $this->converter->convert($bbcode));
     }
 }
diff --git a/tests/Helpers/TreeViewNodeTest.php b/tests/Helpers/TreeViewNodeTest.php
index e0115878..89f3bcce 100644
--- a/tests/Helpers/TreeViewNodeTest.php
+++ b/tests/Helpers/TreeViewNodeTest.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).
  *
@@ -35,7 +38,7 @@ class TreeViewNodeTest extends TestCase
      */
     protected $node2;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $sub_nodes = [];
         $sub_nodes[] = new TreeViewNode('Subnode 1');
@@ -50,16 +53,16 @@ class TreeViewNodeTest extends TestCase
         $this->node2 = new TreeViewNode('Name', 'www.foo.bar', $sub_nodes);
     }
 
-    public function testConstructor()
+    public function testConstructor(): void
     {
         //A node without things should have null values on its properties:
         $this->assertNull($this->node1->getHref());
         $this->assertNull($this->node1->getNodes());
-        $this->assertEquals('Name', $this->node1->getText());
+        $this->assertSame('Name', $this->node1->getText());
 
         //The second node must have the given things as properties.
-        $this->assertEquals('Name', $this->node2->getText());
-        $this->assertEquals('www.foo.bar', $this->node2->getHref());
+        $this->assertSame('Name', $this->node2->getText());
+        $this->assertSame('www.foo.bar', $this->node2->getHref());
         $this->assertNotEmpty($this->node2->getNodes());
     }
 }
diff --git a/tests/Repository/NamedDBElementRepositoryTest.php b/tests/Repository/NamedDBElementRepositoryTest.php
index 66414b4d..0487c9d1 100644
--- a/tests/Repository/NamedDBElementRepositoryTest.php
+++ b/tests/Repository/NamedDBElementRepositoryTest.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).
  *
@@ -35,9 +38,6 @@ class NamedDBElementRepositoryTest extends WebTestCase
     /** @var StructuralDBElementRepository */
     private $repo;
 
-    /**
-     * {@inheritdoc}
-     */
     protected function setUp(): void
     {
         $kernel = self::bootKernel();
@@ -49,14 +49,14 @@ class NamedDBElementRepositoryTest extends WebTestCase
         $this->repo = $this->entityManager->getRepository(User::class);
     }
 
-    public function testGetGenericNodeTree()
+    public function testGetGenericNodeTree(): void
     {
         $tree = $this->repo->getGenericNodeTree();
 
         $this->assertIsArray($tree);
         $this->assertContainsOnlyInstancesOf(TreeViewNode::class, $tree);
         $this->assertCount(4, $tree);
-        $this->assertEquals('admin', $tree[0]->getText());
+        $this->assertSame('admin', $tree[0]->getText());
         $this->assertEmpty($tree[0]->getNodes());
     }
 }
diff --git a/tests/Repository/StructuralDBElementRepositoryTest.php b/tests/Repository/StructuralDBElementRepositoryTest.php
index f568ee65..e3157abc 100644
--- a/tests/Repository/StructuralDBElementRepositoryTest.php
+++ b/tests/Repository/StructuralDBElementRepositoryTest.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).
  *
@@ -35,9 +38,6 @@ class StructuralDBElementRepositoryTest extends WebTestCase
     /** @var StructuralDBElementRepository */
     private $repo;
 
-    /**
-     * {@inheritdoc}
-     */
     protected function setUp(): void
     {
         $kernel = self::bootKernel();
@@ -56,9 +56,9 @@ class StructuralDBElementRepositoryTest extends WebTestCase
         $this->assertContainsOnlyInstancesOf(AttachmentType::class, $root_nodes);
 
         //Asc sorting
-        $this->assertEquals('Node 1', $root_nodes[0]->getName());
-        $this->assertEquals('Node 2', $root_nodes[1]->getName());
-        $this->assertEquals('Node 3', $root_nodes[2]->getName());
+        $this->assertSame('Node 1', $root_nodes[0]->getName());
+        $this->assertSame('Node 2', $root_nodes[1]->getName());
+        $this->assertSame('Node 3', $root_nodes[2]->getName());
     }
 
     public function testGetGenericTree(): void
@@ -74,16 +74,16 @@ class StructuralDBElementRepositoryTest extends WebTestCase
         $this->assertEmpty($tree[1]->getNodes()[0]->getNodes());
 
         //Check text
-        $this->assertEquals('Node 1', $tree[0]->getText());
-        $this->assertEquals('Node 2', $tree[1]->getText());
-        $this->assertEquals('Node 3', $tree[2]->getText());
-        $this->assertEquals('Node 1.1', $tree[0]->getNodes()[0]->getText());
-        $this->assertEquals('Node 1.1.1', $tree[0]->getNodes()[0]->getNodes()[0]->getText());
+        $this->assertSame('Node 1', $tree[0]->getText());
+        $this->assertSame('Node 2', $tree[1]->getText());
+        $this->assertSame('Node 3', $tree[2]->getText());
+        $this->assertSame('Node 1.1', $tree[0]->getNodes()[0]->getText());
+        $this->assertSame('Node 1.1.1', $tree[0]->getNodes()[0]->getNodes()[0]->getText());
 
         //Check that IDs were set correctly
-        $this->assertEquals(1, $tree[0]->getId());
-        $this->assertEquals(2, $tree[1]->getId());
-        $this->assertEquals(7, $tree[0]->getNodes()[0]->getNodes()[0]->getId());
+        $this->assertSame(1, $tree[0]->getId());
+        $this->assertSame(2, $tree[1]->getId());
+        $this->assertSame(7, $tree[0]->getNodes()[0]->getNodes()[0]->getId());
     }
 
     /**
@@ -96,13 +96,13 @@ class StructuralDBElementRepositoryTest extends WebTestCase
 
         $this->assertCount(7, $nodes);
         $this->assertContainsOnlyInstancesOf(AttachmentType::class, $nodes);
-        $this->assertEquals('Node 1', $nodes[0]->getName());
-        $this->assertEquals('Node 1.1', $nodes[1]->getName());
-        $this->assertEquals('Node 1.1.1', $nodes[2]->getName());
-        $this->assertEquals('Node 1.2', $nodes[3]->getName());
-        $this->assertEquals('Node 2', $nodes[4]->getName());
-        $this->assertEquals('Node 2.1', $nodes[5]->getName());
-        $this->assertEquals('Node 3', $nodes[6]->getName());
+        $this->assertSame('Node 1', $nodes[0]->getName());
+        $this->assertSame('Node 1.1', $nodes[1]->getName());
+        $this->assertSame('Node 1.1.1', $nodes[2]->getName());
+        $this->assertSame('Node 1.2', $nodes[3]->getName());
+        $this->assertSame('Node 2', $nodes[4]->getName());
+        $this->assertSame('Node 2.1', $nodes[5]->getName());
+        $this->assertSame('Node 3', $nodes[6]->getName());
     }
 
     public function testToNodesListElement(): void
@@ -113,8 +113,8 @@ class StructuralDBElementRepositoryTest extends WebTestCase
 
         $this->assertCount(3, $nodes);
         $this->assertContainsOnlyInstancesOf(AttachmentType::class, $nodes);
-        $this->assertEquals('Node 1.1', $nodes[0]->getName());
-        $this->assertEquals('Node 1.1.1', $nodes[1]->getName());
-        $this->assertEquals('Node 1.2', $nodes[2]->getName());
+        $this->assertSame('Node 1.1', $nodes[0]->getName());
+        $this->assertSame('Node 1.1.1', $nodes[1]->getName());
+        $this->assertSame('Node 1.2', $nodes[2]->getName());
     }
 }
diff --git a/tests/Security/Annotations/ColumnSecurityTest.php b/tests/Security/Annotations/ColumnSecurityTest.php
index 51d7959d..113e80ab 100644
--- a/tests/Security/Annotations/ColumnSecurityTest.php
+++ b/tests/Security/Annotations/ColumnSecurityTest.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).
  *
@@ -27,24 +30,24 @@ use PHPUnit\Framework\TestCase;
 
 class ColumnSecurityTest extends TestCase
 {
-    public function testGetReadOperation()
+    public function testGetReadOperation(): void
     {
         $annotation = new ColumnSecurity();
-        $this->assertEquals('read', $annotation->getReadOperationName(), 'A new annotation must return read');
+        $this->assertSame('read', $annotation->getReadOperationName(), 'A new annotation must return read');
         $annotation->read = 'overwritten';
-        $this->assertEquals('overwritten', $annotation->getReadOperationName());
+        $this->assertSame('overwritten', $annotation->getReadOperationName());
         $annotation->prefix = 'prefix';
-        $this->assertEquals('prefix.overwritten', $annotation->getReadOperationName());
+        $this->assertSame('prefix.overwritten', $annotation->getReadOperationName());
     }
 
-    public function testGetEditOperation()
+    public function testGetEditOperation(): void
     {
         $annotation = new ColumnSecurity();
-        $this->assertEquals('edit', $annotation->getEditOperationName(), 'A new annotation must return read');
+        $this->assertSame('edit', $annotation->getEditOperationName(), 'A new annotation must return read');
         $annotation->edit = 'overwritten';
-        $this->assertEquals('overwritten', $annotation->getEditOperationName());
+        $this->assertSame('overwritten', $annotation->getEditOperationName());
         $annotation->prefix = 'prefix';
-        $this->assertEquals('prefix.overwritten', $annotation->getEditOperationName());
+        $this->assertSame('prefix.overwritten', $annotation->getEditOperationName());
     }
 
     public function placeholderScalarDataProvider(): array
@@ -66,18 +69,18 @@ class ColumnSecurityTest extends TestCase
      *
      * @param $expected_value
      */
-    public function testGetPlaceholderScalar(string $type, $expected_value)
+    public function testGetPlaceholderScalar(string $type, $expected_value): void
     {
         $annotation = new ColumnSecurity();
         $annotation->type = $type;
-        $this->assertEquals($expected_value, $annotation->getPlaceholder());
+        $this->assertSame($expected_value, $annotation->getPlaceholder());
     }
 
-    public function testGetPlaceholderSpecifiedValue()
+    public function testGetPlaceholderSpecifiedValue(): void
     {
         $annotation = new ColumnSecurity();
         $annotation->placeholder = 3434;
-        $this->assertEquals(3434, $annotation->getPlaceholder());
+        $this->assertSame(3434, $annotation->getPlaceholder());
 
         $annotation->placeholder = [323];
         $this->assertCount(1, $annotation->getPlaceholder());
@@ -85,10 +88,10 @@ class ColumnSecurityTest extends TestCase
         //If a placeholder is specified we allow every type
         $annotation->type = 'type2';
         $annotation->placeholder = 'invalid';
-        $this->assertEquals('invalid', $annotation->getPlaceholder());
+        $this->assertSame('invalid', $annotation->getPlaceholder());
     }
 
-    public function testGetPlaceholderDBElement()
+    public function testGetPlaceholderDBElement(): void
     {
         $annotation = new ColumnSecurity();
         $annotation->type = AttachmentType::class;
@@ -96,11 +99,11 @@ class ColumnSecurityTest extends TestCase
         /** @var AttachmentType $placeholder */
         $placeholder = $annotation->getPlaceholder();
         $this->assertInstanceOf(AttachmentType::class, $placeholder);
-        $this->assertEquals('???', $placeholder->getName());
+        $this->assertSame('???', $placeholder->getName());
 
         $annotation->placeholder = 'test';
         $placeholder = $annotation->getPlaceholder();
         $this->assertInstanceOf(AttachmentType::class, $placeholder);
-        $this->assertEquals('test', $placeholder->getName());
+        $this->assertSame('test', $placeholder->getName());
     }
 }
diff --git a/tests/Security/UserCheckerTest.php b/tests/Security/UserCheckerTest.php
index edb17f74..9835467c 100644
--- a/tests/Security/UserCheckerTest.php
+++ b/tests/Security/UserCheckerTest.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).
  *
@@ -30,12 +33,12 @@ class UserCheckerTest extends TestCase
 {
     protected $service;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         $this->service = new UserChecker();
     }
 
-    public function testThrowDisabledException()
+    public function testThrowDisabledException(): void
     {
         $user = new User();
         $user->setDisabled(false);
diff --git a/tests/Services/AmountFormatterTest.php b/tests/Services/AmountFormatterTest.php
index c1aa6826..85dee35f 100644
--- a/tests/Services/AmountFormatterTest.php
+++ b/tests/Services/AmountFormatterTest.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).
  *
@@ -32,7 +35,7 @@ class AmountFormatterTest extends WebTestCase
      */
     protected $service;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp(); // TODO: Change the autogenerated stub
 
@@ -41,56 +44,56 @@ class AmountFormatterTest extends WebTestCase
         $this->service = self::$container->get(AmountFormatter::class);
     }
 
-    public function testFormatWithoutUnit()
+    public function testFormatWithoutUnit(): void
     {
-        $this->assertEquals('2', $this->service->format(2.321));
-        $this->assertEquals('1002', $this->service->format(1002.356));
-        $this->assertEquals('1000454', $this->service->format(1000454.0));
-        $this->assertEquals('0', $this->service->format(0.01));
-        $this->assertEquals('0', $this->service->format(0));
+        $this->assertSame('2', $this->service->format(2.321));
+        $this->assertSame('1002', $this->service->format(1002.356));
+        $this->assertSame('1000454', $this->service->format(1000454.0));
+        $this->assertSame('0', $this->service->format(0.01));
+        $this->assertSame('0', $this->service->format(0));
     }
 
-    public function testInvalidInput()
+    public function testInvalidInput(): void
     {
         $this->expectException(\InvalidArgumentException::class);
         $this->service->format('test');
     }
 
-    public function testFormatUnitWithoutSI()
+    public function testFormatUnitWithoutSI(): void
     {
         $meters = new MeasurementUnit();
         $meters->setIsInteger(false)->setUseSIPrefix(false)->setUnit('m');
 
-        $this->assertEquals('0.32 m', $this->service->format(0.3245, $meters));
-        $this->assertEquals('10003.56 m', $this->service->format(10003.556, $meters));
-        $this->assertEquals('0.00 m', $this->service->format(0.0004, $meters));
+        $this->assertSame('0.32 m', $this->service->format(0.3245, $meters));
+        $this->assertSame('10003.56 m', $this->service->format(10003.556, $meters));
+        $this->assertSame('0.00 m', $this->service->format(0.0004, $meters));
     }
 
-    public function testFormatUnitWithSI()
+    public function testFormatUnitWithSI(): void
     {
         $meters = new MeasurementUnit();
         $meters->setIsInteger(false)->setUseSIPrefix(true)->setUnit('m');
 
-        $this->assertEquals('0.32 m', $this->service->format(0.3245, $meters));
-        $this->assertEquals('12.32 m', $this->service->format(12.323, $meters));
-        $this->assertEquals('120.32 km', $this->service->format(120320.45, $meters));
+        $this->assertSame('0.32 m', $this->service->format(0.3245, $meters));
+        $this->assertSame('12.32 m', $this->service->format(12.323, $meters));
+        $this->assertSame('120.32 km', $this->service->format(120320.45, $meters));
 
-        $this->assertEquals('0.32 mm', $this->service->format(0.00032, $meters));
+        $this->assertSame('0.32 mm', $this->service->format(0.00032, $meters));
     }
 
-    public function testFormatMoreDigits()
+    public function testFormatMoreDigits(): void
     {
-        $this->assertEquals('12.12345', $this->service->format(12.1234532, null, ['is_integer' => false, 'decimals' => 5]));
-        $this->assertEquals('12.1', $this->service->format(12.1234532, null, ['is_integer' => false, 'decimals' => 1]));
+        $this->assertSame('12.12345', $this->service->format(12.1234532, null, ['is_integer' => false, 'decimals' => 5]));
+        $this->assertSame('12.1', $this->service->format(12.1234532, null, ['is_integer' => false, 'decimals' => 1]));
     }
 
-    public function testFormatOptionsOverride()
+    public function testFormatOptionsOverride(): void
     {
         $meters = new MeasurementUnit();
         $meters->setIsInteger(false)->setUseSIPrefix(true)->setUnit('m');
 
-        $this->assertEquals('12.32', $this->service->format(12.323, $meters, ['unit' => '']));
-        $this->assertEquals('12002.32 m', $this->service->format(12002.32, $meters, ['show_prefix' => false]));
-        $this->assertEquals('123 m', $this->service->format(123.234, $meters, ['is_integer' => true]));
+        $this->assertSame('12.32', $this->service->format(12.323, $meters, ['unit' => '']));
+        $this->assertSame('12002.32 m', $this->service->format(12002.32, $meters, ['show_prefix' => false]));
+        $this->assertSame('123 m', $this->service->format(123.234, $meters, ['is_integer' => true]));
     }
 }
diff --git a/tests/Services/Attachments/AttachmentPathResolverTest.php b/tests/Services/Attachments/AttachmentPathResolverTest.php
index 19093550..26be1b19 100644
--- a/tests/Services/Attachments/AttachmentPathResolverTest.php
+++ b/tests/Services/Attachments/AttachmentPathResolverTest.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).
  *
@@ -27,6 +30,8 @@ use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
 
 class AttachmentPathResolverTest extends WebTestCase
 {
+    public static $media_path;
+    public static $footprint_path;
     /**
      * @var AmountFormatter
      */
@@ -34,9 +39,6 @@ class AttachmentPathResolverTest extends WebTestCase
     protected static $projectDir_orig;
     protected static $projectDir;
 
-    public static $media_path;
-    public static $footprint_path;
-
     public function __construct($name = null, array $data = [], $dataName = '')
     {
         parent::__construct($name, $data, $dataName);
@@ -57,17 +59,17 @@ class AttachmentPathResolverTest extends WebTestCase
         self::$service = self::$container->get(AttachmentPathResolver::class);
     }
 
-    public function testParameterToAbsolutePath()
+    public function testParameterToAbsolutePath(): void
     {
         //If null is passed, null must be returned
         $this->assertNull(self::$service->parameterToAbsolutePath(null));
 
         //Absolute path should be returned like they are (we use projectDir here, because we know that this dir exists)
-        $this->assertEquals(self::$projectDir_orig, self::$service->parameterToAbsolutePath(self::$projectDir));
+        $this->assertSame(self::$projectDir_orig, self::$service->parameterToAbsolutePath(self::$projectDir));
 
         //Relative pathes should be resolved
-        $this->assertEquals(self::$projectDir_orig.\DIRECTORY_SEPARATOR.'src', self::$service->parameterToAbsolutePath('src'));
-        $this->assertEquals(self::$projectDir_orig.\DIRECTORY_SEPARATOR.'src', self::$service->parameterToAbsolutePath('./src'));
+        $this->assertSame(self::$projectDir_orig.\DIRECTORY_SEPARATOR.'src', self::$service->parameterToAbsolutePath('src'));
+        $this->assertSame(self::$projectDir_orig.\DIRECTORY_SEPARATOR.'src', self::$service->parameterToAbsolutePath('./src'));
 
         //Invalid pathes should return null
         $this->assertNull(self::$service->parameterToAbsolutePath('/this/path/does/not/exist'));
@@ -116,16 +118,16 @@ class AttachmentPathResolverTest extends WebTestCase
     /**
      * @dataProvider placeholderDataProvider
      */
-    public function testPlaceholderToRealPath($param, $expected)
+    public function testPlaceholderToRealPath($param, $expected): void
     {
-        $this->assertEquals($expected, self::$service->placeholderToRealPath($param));
+        $this->assertSame($expected, self::$service->placeholderToRealPath($param));
     }
 
     /**
      * @dataProvider realPathDataProvider
      */
-    public function testRealPathToPlaceholder($param, $expected, $old_method = false)
+    public function testRealPathToPlaceholder($param, $expected, $old_method = false): void
     {
-        $this->assertEquals($expected, self::$service->realPathToPlaceholder($param, $old_method));
+        $this->assertSame($expected, self::$service->realPathToPlaceholder($param, $old_method));
     }
 }
diff --git a/tests/Services/Attachments/AttachmentURLGeneratorTest.php b/tests/Services/Attachments/AttachmentURLGeneratorTest.php
index cf094c72..f6db98c5 100644
--- a/tests/Services/Attachments/AttachmentURLGeneratorTest.php
+++ b/tests/Services/Attachments/AttachmentURLGeneratorTest.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).
  *
@@ -54,8 +57,8 @@ class AttachmentURLGeneratorTest extends WebTestCase
      * @param $input
      * @param $expected
      */
-    public function testabsolutePathToAssetPath($input, $expected)
+    public function testTestabsolutePathToAssetPath($input, $expected): void
     {
-        $this->assertEquals($expected, static::$service->absolutePathToAssetPath($input, static::PUBLIC_DIR));
+        $this->assertSame($expected, static::$service->absolutePathToAssetPath($input, static::PUBLIC_DIR));
     }
 }
diff --git a/tests/Services/Attachments/BuiltinAttachmentsFinderTest.php b/tests/Services/Attachments/BuiltinAttachmentsFinderTest.php
index 43329df7..04b37d74 100644
--- a/tests/Services/Attachments/BuiltinAttachmentsFinderTest.php
+++ b/tests/Services/Attachments/BuiltinAttachmentsFinderTest.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).
  *
@@ -60,11 +63,11 @@ class BuiltinAttachmentsFinderTest extends WebTestCase
     /**
      * @dataProvider dataProvider
      */
-    public function testFind($keyword, $options, $expected)
+    public function testFind($keyword, $options, $expected): void
     {
         $value = static::$service->find($keyword, $options, static::$mock_list);
         //$this->assertEquals($expected, static::$service->find($keyword, $options, static::$mock_list));
-        $this->assertEquals([], array_diff($value, $expected), 'Additional');
-        $this->assertEquals([], array_diff($expected, $value), 'Missing:');
+        $this->assertSame([], array_diff($value, $expected), 'Additional');
+        $this->assertSame([], array_diff($expected, $value), 'Missing:');
     }
 }
diff --git a/tests/Services/Attachments/FileTypeFilterToolsTest.php b/tests/Services/Attachments/FileTypeFilterToolsTest.php
index b4d940f4..99d3e6d6 100644
--- a/tests/Services/Attachments/FileTypeFilterToolsTest.php
+++ b/tests/Services/Attachments/FileTypeFilterToolsTest.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).
  *
@@ -91,24 +94,24 @@ class FileTypeFilterToolsTest extends WebTestCase
      *
      * @dataProvider validateDataProvider
      */
-    public function testValidateFilterString(string $filter, bool $expected)
+    public function testValidateFilterString(string $filter, bool $expected): void
     {
-        $this->assertEquals($expected, self::$service->validateFilterString($filter));
+        $this->assertSame($expected, self::$service->validateFilterString($filter));
     }
 
     /**
      * @dataProvider normalizeDataProvider
      */
-    public function testNormalizeFilterString(string $filter, string $expected)
+    public function testNormalizeFilterString(string $filter, string $expected): void
     {
-        $this->assertEquals($expected, self::$service->normalizeFilterString($filter));
+        $this->assertSame($expected, self::$service->normalizeFilterString($filter));
     }
 
     /**
      * @dataProvider extensionAllowedDataProvider
      */
-    public function testIsExtensionAllowed(string $filter, string $extension, bool $expected)
+    public function testIsExtensionAllowed(string $filter, string $extension, bool $expected): void
     {
-        $this->assertEquals($expected, self::$service->isExtensionAllowed($filter, $extension), $expected);
+        $this->assertSame($expected, self::$service->isExtensionAllowed($filter, $extension));
     }
 }
diff --git a/tests/Services/ElementTypeNameGeneratorTest.php b/tests/Services/ElementTypeNameGeneratorTest.php
index 1fdf4aff..eb55e2cb 100644
--- a/tests/Services/ElementTypeNameGeneratorTest.php
+++ b/tests/Services/ElementTypeNameGeneratorTest.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).
  *
@@ -38,7 +41,7 @@ class ElementTypeNameGeneratorTest extends WebTestCase
      */
     protected $service;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
@@ -47,14 +50,14 @@ class ElementTypeNameGeneratorTest extends WebTestCase
         $this->service = self::$container->get(ElementTypeNameGenerator::class);
     }
 
-    public function testGetLocalizedTypeNameCombination()
+    public function testGetLocalizedTypeNameCombination(): void
     {
         //We only test in english
-        $this->assertEquals('Part', $this->service->getLocalizedTypeLabel(new Part()));
-        $this->assertEquals('Category', $this->service->getLocalizedTypeLabel(new Category()));
+        $this->assertSame('Part', $this->service->getLocalizedTypeLabel(new Part()));
+        $this->assertSame('Category', $this->service->getLocalizedTypeLabel(new Category()));
 
         //Test inheritance
-        $this->assertEquals('Attachment', $this->service->getLocalizedTypeLabel(new PartAttachment()));
+        $this->assertSame('Attachment', $this->service->getLocalizedTypeLabel(new PartAttachment()));
 
         //Test exception for unknpwn type
         $this->expectException(EntityNotSupportedException::class);
@@ -66,14 +69,14 @@ class ElementTypeNameGeneratorTest extends WebTestCase
         });
     }
 
-    public function testGetTypeNameCombination()
+    public function testGetTypeNameCombination(): void
     {
         $part = new Part();
         $part->setName('Test<Part');
         //When the text version is used, dont escape the name
-        $this->assertEquals('Part: Test<Part', $this->service->getTypeNameCombination($part, false));
+        $this->assertSame('Part: Test<Part', $this->service->getTypeNameCombination($part, false));
 
-        $this->assertEquals('<i>Part:</i> Test&lt;Part', $this->service->getTypeNameCombination($part, true));
+        $this->assertSame('<i>Part:</i> Test&lt;Part', $this->service->getTypeNameCombination($part, true));
 
         //Test exception
         $this->expectException(EntityNotSupportedException::class);
diff --git a/tests/Services/EntityImporterTest.php b/tests/Services/EntityImporterTest.php
index 76d16284..9fabcaaa 100644
--- a/tests/Services/EntityImporterTest.php
+++ b/tests/Services/EntityImporterTest.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).
  *
@@ -36,7 +39,7 @@ class EntityImporterTest extends WebTestCase
      */
     protected $service;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
 
@@ -45,7 +48,7 @@ class EntityImporterTest extends WebTestCase
         $this->service = self::$container->get(EntityImporter::class);
     }
 
-    public function testMassCreationResults()
+    public function testMassCreationResults(): void
     {
         $errors = [];
         $results = $this->service->massCreation('', AttachmentType::class, null, $errors);
@@ -60,26 +63,26 @@ class EntityImporterTest extends WebTestCase
         //Check type
         $this->assertInstanceOf(AttachmentType::class, $results[0]);
         //Check names
-        $this->assertEquals('Test 1', $results[0]->getName());
-        $this->assertEquals('Test 2', $results[1]->getName());
+        $this->assertSame('Test 1', $results[0]->getName());
+        $this->assertSame('Test 2', $results[1]->getName());
         //Check parent
         $this->assertNull($results[0]->getMasterPictureAttachment());
 
         $parent = new AttachmentType();
         $results = $this->service->massCreation($lines, AttachmentType::class, $parent, $errors);
         $this->assertCount(3, $results);
-        $this->assertEquals($parent, $results[0]->getParent());
+        $this->assertSame($parent, $results[0]->getParent());
     }
 
-    public function testMassCreationErrors()
+    public function testMassCreationErrors(): void
     {
         $errors = [];
         //Node 1 and Node 2 are created in datafixtures, so their attemp to create them again must fail.
         $lines = "Test 1 \n Node 1 \n Node 2";
         $results = $this->service->massCreation($lines, AttachmentType::class, null, $errors);
         $this->assertCount(1, $results);
-        $this->assertEquals('Test 1', $results[0]->getName());
+        $this->assertSame('Test 1', $results[0]->getName());
         $this->assertCount(2, $errors);
-        $this->assertEquals('Node 1', $errors[0]['entity']->getName());
+        $this->assertSame('Node 1', $errors[0]['entity']->getName());
     }
 }
diff --git a/tests/Services/FAIconGeneratorTest.php b/tests/Services/FAIconGeneratorTest.php
index 0d1498b3..0d935a0f 100644
--- a/tests/Services/FAIconGeneratorTest.php
+++ b/tests/Services/FAIconGeneratorTest.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).
  *
@@ -31,7 +34,7 @@ class FAIconGeneratorTest extends WebTestCase
      */
     protected $service;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp(); // TODO: Change the autogenerated stub
 
@@ -57,15 +60,15 @@ class FAIconGeneratorTest extends WebTestCase
     /**
      * @dataProvider fileExtensionDataProvider
      */
-    public function testFileExtensionToFAType(string $ext, string $expected)
+    public function testFileExtensionToFAType(string $ext, string $expected): void
     {
-        $this->assertEquals($expected, $this->service->fileExtensionToFAType($ext));
+        $this->assertSame($expected, $this->service->fileExtensionToFAType($ext));
     }
 
-    public function testGenerateIconHTML()
+    public function testGenerateIconHTML(): void
     {
-        $this->assertEquals('<i class="fas fa-file "></i>', $this->service->generateIconHTML('fa-file'));
-        $this->assertEquals('<i class="far fa-file "></i>', $this->service->generateIconHTML('fa-file', 'far'));
-        $this->assertEquals('<i class="far fa-file fa-2x"></i>', $this->service->generateIconHTML('fa-file', 'far', 'fa-2x'));
+        $this->assertSame('<i class="fas fa-file "></i>', $this->service->generateIconHTML('fa-file'));
+        $this->assertSame('<i class="far fa-file "></i>', $this->service->generateIconHTML('fa-file', 'far'));
+        $this->assertSame('<i class="far fa-file fa-2x"></i>', $this->service->generateIconHTML('fa-file', 'far', 'fa-2x'));
     }
 }
diff --git a/tests/Services/PermissionResolverTest.php b/tests/Services/PermissionResolverTest.php
index 055e054c..09461d82 100644
--- a/tests/Services/PermissionResolverTest.php
+++ b/tests/Services/PermissionResolverTest.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).
  *
@@ -38,7 +41,7 @@ class PermissionResolverTest extends WebTestCase
     protected $user_withoutGroup;
     protected $group;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp(); // TODO: Change the autogenerated stub
 
@@ -119,7 +122,7 @@ class PermissionResolverTest extends WebTestCase
     /**
      * @dataProvider getPermissionNames
      */
-    public function testListOperationsForPermission($perm_name)
+    public function testListOperationsForPermission($perm_name): void
     {
         $arr = $this->service->listOperationsForPermission($perm_name);
 
@@ -127,20 +130,20 @@ class PermissionResolverTest extends WebTestCase
         $this->assertNotEmpty($arr);
     }
 
-    public function testInvalidListOperationsForPermission()
+    public function testInvalidListOperationsForPermission(): void
     {
         $this->expectException(\InvalidArgumentException::class);
         //Must throw an exception
         $this->service->listOperationsForPermission('invalid');
     }
 
-    public function testisValidPermission()
+    public function testisValidPermission(): void
     {
         $this->assertTrue($this->service->isValidPermission('parts'));
         $this->assertFalse($this->service->isValidPermission('invalid'));
     }
 
-    public function testIsValidOperation()
+    public function testIsValidOperation(): void
     {
         $this->assertTrue($this->service->isValidOperation('parts', 'read'));
 
@@ -150,7 +153,7 @@ class PermissionResolverTest extends WebTestCase
         $this->assertFalse($this->service->isValidOperation('invalid', 'invalid'));
     }
 
-    public function testDontInherit()
+    public function testDontInherit(): void
     {
         //Check with faked object
         $this->assertTrue($this->service->dontInherit($this->user, 'parts', 'read'));
@@ -167,7 +170,7 @@ class PermissionResolverTest extends WebTestCase
         $this->assertNull($this->service->dontInherit($this->user_withoutGroup, 'parts', 'delete'));
     }
 
-    public function testInherit()
+    public function testInherit(): void
     {
         //Not inherited values should be same as dont inherit:
         $this->assertTrue($this->service->inherit($this->user, 'parts', 'read'));
diff --git a/tests/Services/PricedetailHelperTest.php b/tests/Services/PricedetailHelperTest.php
index 7fc40074..8beb7af5 100644
--- a/tests/Services/PricedetailHelperTest.php
+++ b/tests/Services/PricedetailHelperTest.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).
  *
@@ -35,7 +38,7 @@ class PricedetailHelperTest extends WebTestCase
      */
     protected $service;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp();
         //Get an service instance.
@@ -84,8 +87,8 @@ class PricedetailHelperTest extends WebTestCase
     /**
      * @dataProvider maxDiscountAmountDataProvider
      */
-    public function testGetMaxDiscountAmount(Part $part, ?float $expected_result, string $message)
+    public function testGetMaxDiscountAmount(Part $part, ?float $expected_result, string $message): void
     {
-        $this->assertEquals($expected_result, $this->service->getMaxDiscountAmount($part), $message);
+        $this->assertSame($expected_result, $this->service->getMaxDiscountAmount($part), $message);
     }
 }
diff --git a/tests/Services/SIFormatterTest.php b/tests/Services/SIFormatterTest.php
index f75611af..e786808e 100644
--- a/tests/Services/SIFormatterTest.php
+++ b/tests/Services/SIFormatterTest.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).
  *
@@ -31,7 +34,7 @@ class SIFormatterTest extends WebTestCase
      */
     protected $service;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         //Get an service instance.
         self::bootKernel();
@@ -40,7 +43,7 @@ class SIFormatterTest extends WebTestCase
         $this->service = new SIFormatter();
     }
 
-    public function testGetMagnitude()
+    public function testGetMagnitude(): void
     {
         //Get an service instance.
         $this->assertSame(0, $this->service->getMagnitude(7.0));
@@ -61,7 +64,7 @@ class SIFormatterTest extends WebTestCase
         $this->assertSame(12, $this->service->getMagnitude(9.99e12));
     }
 
-    public function testgetPrefixByMagnitude()
+    public function testgetPrefixByMagnitude(): void
     {
         $this->assertSame([1, ''], $this->service->getPrefixByMagnitude(2));
 
@@ -74,10 +77,10 @@ class SIFormatterTest extends WebTestCase
         $this->assertSame([0.001, 'm'], $this->service->getPrefixByMagnitude(-4));
     }
 
-    public function testFormat()
+    public function testFormat(): void
     {
         $this->assertSame('2.32 km', $this->service->format(2321, 'm'));
-        $this->assertEquals('230.45 km', $this->service->format(230450.3, 'm'));
+        $this->assertSame('230.45 km', $this->service->format(230450.3, 'm'));
         $this->assertSame('-98.20 mg', $this->service->format(-0.0982, 'g'));
         $this->assertSame('-0.23 g', $this->service->format(-0.23, 'g'));
     }
diff --git a/tests/Services/TFA/BackupCodeGeneratorTest.php b/tests/Services/TFA/BackupCodeGeneratorTest.php
index 753b49d8..87e2320a 100644
--- a/tests/Services/TFA/BackupCodeGeneratorTest.php
+++ b/tests/Services/TFA/BackupCodeGeneratorTest.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).
  *
@@ -29,7 +32,7 @@ class BackupCodeGeneratorTest extends TestCase
     /**
      * Test if an exception is thrown if you are using a too high code length.
      */
-    public function testLengthUpperLimit()
+    public function testLengthUpperLimit(): void
     {
         $this->expectException(\RuntimeException::class);
         new BackupCodeGenerator(33, 10);
@@ -38,7 +41,7 @@ class BackupCodeGeneratorTest extends TestCase
     /**
      * Test if an exception is thrown if you are using a too high code length.
      */
-    public function testLengthLowerLimit()
+    public function testLengthLowerLimit(): void
     {
         $this->expectException(\RuntimeException::class);
         new BackupCodeGenerator(4, 10);
@@ -52,7 +55,7 @@ class BackupCodeGeneratorTest extends TestCase
     /**
      * @dataProvider  codeLengthDataProvider
      */
-    public function testGenerateSingleCode(int $code_length)
+    public function testGenerateSingleCode(int $code_length): void
     {
         $generator = new BackupCodeGenerator($code_length, 10);
         $this->assertRegExp("/^([a-f0-9]){{$code_length}}\$/", $generator->generateSingleCode());
@@ -66,7 +69,7 @@ class BackupCodeGeneratorTest extends TestCase
     /**
      * @dataProvider codeCountDataProvider
      */
-    public function testGenerateCodeSet(int $code_count)
+    public function testGenerateCodeSet(int $code_count): void
     {
         $generator = new BackupCodeGenerator(8, $code_count);
         $this->assertCount($code_count, $generator->generateCodeSet());
diff --git a/tests/Services/TFA/BackupCodeManagerTest.php b/tests/Services/TFA/BackupCodeManagerTest.php
index 5bef0aa8..8c6ac743 100644
--- a/tests/Services/TFA/BackupCodeManagerTest.php
+++ b/tests/Services/TFA/BackupCodeManagerTest.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).
  *
@@ -32,22 +35,22 @@ class BackupCodeManagerTest extends WebTestCase
      */
     protected $service;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         self::bootKernel();
         $this->service = self::$container->get(BackupCodeManager::class);
     }
 
-    public function testRegenerateBackupCodes()
+    public function testRegenerateBackupCodes(): void
     {
         $user = new User();
         $old_codes = ['aaaa', 'bbbb'];
         $user->setBackupCodes($old_codes);
         $this->service->regenerateBackupCodes($user);
-        $this->assertNotEquals($old_codes, $user->getBackupCodes());
+        $this->assertNotSame($old_codes, $user->getBackupCodes());
     }
 
-    public function testEnableBackupCodes()
+    public function testEnableBackupCodes(): void
     {
         $user = new User();
         //Check that nothing is changed, if there are already backup codes
@@ -55,7 +58,7 @@ class BackupCodeManagerTest extends WebTestCase
         $old_codes = ['aaaa', 'bbbb'];
         $user->setBackupCodes($old_codes);
         $this->service->enableBackupCodes($user);
-        $this->assertEquals($old_codes, $user->getBackupCodes());
+        $this->assertSame($old_codes, $user->getBackupCodes());
 
         //When no old codes are existing, it should generate a set
         $user->setBackupCodes([]);
@@ -63,7 +66,7 @@ class BackupCodeManagerTest extends WebTestCase
         $this->assertNotEmpty($user->getBackupCodes());
     }
 
-    public function testDisableBackupCodesIfUnused()
+    public function testDisableBackupCodesIfUnused(): void
     {
         $user = new User();
 
@@ -77,6 +80,6 @@ class BackupCodeManagerTest extends WebTestCase
 
         $user->setGoogleAuthenticatorSecret('jskf');
         $this->service->disableBackupCodesIfUnused($user);
-        $this->assertEquals($codes, $user->getBackupCodes());
+        $this->assertSame($codes, $user->getBackupCodes());
     }
 }
diff --git a/tests/Services/Trees/NodesListBuilderTest.php b/tests/Services/Trees/NodesListBuilderTest.php
index 7266fe1a..37e963e0 100644
--- a/tests/Services/Trees/NodesListBuilderTest.php
+++ b/tests/Services/Trees/NodesListBuilderTest.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).
  *
@@ -37,7 +40,7 @@ class NodesListBuilderTest extends WebTestCase
     protected $service;
     protected $em;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         self::bootKernel();
         $this->service = self::$container->get(NodesListBuilder::class);
@@ -54,13 +57,13 @@ class NodesListBuilderTest extends WebTestCase
 
         $this->assertCount(7, $nodes);
         $this->assertContainsOnlyInstancesOf(AttachmentType::class, $nodes);
-        $this->assertEquals('Node 1', $nodes[0]->getName());
-        $this->assertEquals('Node 1.1', $nodes[1]->getName());
-        $this->assertEquals('Node 1.1.1', $nodes[2]->getName());
-        $this->assertEquals('Node 1.2', $nodes[3]->getName());
-        $this->assertEquals('Node 2', $nodes[4]->getName());
-        $this->assertEquals('Node 2.1', $nodes[5]->getName());
-        $this->assertEquals('Node 3', $nodes[6]->getName());
+        $this->assertSame('Node 1', $nodes[0]->getName());
+        $this->assertSame('Node 1.1', $nodes[1]->getName());
+        $this->assertSame('Node 1.1.1', $nodes[2]->getName());
+        $this->assertSame('Node 1.2', $nodes[3]->getName());
+        $this->assertSame('Node 2', $nodes[4]->getName());
+        $this->assertSame('Node 2.1', $nodes[5]->getName());
+        $this->assertSame('Node 3', $nodes[6]->getName());
     }
 
     public function testTypeToNodesListElement(): void
@@ -71,8 +74,8 @@ class NodesListBuilderTest extends WebTestCase
 
         $this->assertCount(3, $nodes);
         $this->assertContainsOnlyInstancesOf(AttachmentType::class, $nodes);
-        $this->assertEquals('Node 1.1', $nodes[0]->getName());
-        $this->assertEquals('Node 1.1.1', $nodes[1]->getName());
-        $this->assertEquals('Node 1.2', $nodes[2]->getName());
+        $this->assertSame('Node 1.1', $nodes[0]->getName());
+        $this->assertSame('Node 1.1.1', $nodes[1]->getName());
+        $this->assertSame('Node 1.2', $nodes[2]->getName());
     }
 }
diff --git a/tests/Services/Trees/TreeViewGeneratorTest.php b/tests/Services/Trees/TreeViewGeneratorTest.php
index 43e57eaf..74c1c521 100644
--- a/tests/Services/Trees/TreeViewGeneratorTest.php
+++ b/tests/Services/Trees/TreeViewGeneratorTest.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).
  *
@@ -39,7 +42,7 @@ class TreeViewGeneratorTest extends WebTestCase
     protected $service;
     protected $em;
 
-    public function setUp(): void
+    protected function setUp(): void
     {
         parent::setUp(); // TODO: Change the autogenerated stub
 
@@ -49,7 +52,7 @@ class TreeViewGeneratorTest extends WebTestCase
         $this->em = self::$container->get(EntityManagerInterface::class);
     }
 
-    public function testGetGenericTree()
+    public function testGetGenericTree(): void
     {
         $tree = $this->service->getGenericTree(AttachmentType::class, null);
 
@@ -63,19 +66,19 @@ class TreeViewGeneratorTest extends WebTestCase
         $this->assertEmpty($tree[1]->getNodes()[0]->getNodes());
 
         //Check text
-        $this->assertEquals('Node 1', $tree[0]->getText());
-        $this->assertEquals('Node 2', $tree[1]->getText());
-        $this->assertEquals('Node 3', $tree[2]->getText());
-        $this->assertEquals('Node 1.1', $tree[0]->getNodes()[0]->getText());
-        $this->assertEquals('Node 1.1.1', $tree[0]->getNodes()[0]->getNodes()[0]->getText());
+        $this->assertSame('Node 1', $tree[0]->getText());
+        $this->assertSame('Node 2', $tree[1]->getText());
+        $this->assertSame('Node 3', $tree[2]->getText());
+        $this->assertSame('Node 1.1', $tree[0]->getNodes()[0]->getText());
+        $this->assertSame('Node 1.1.1', $tree[0]->getNodes()[0]->getNodes()[0]->getText());
 
         //Check that IDs were set correctly
-        $this->assertEquals(1, $tree[0]->getId());
-        $this->assertEquals(2, $tree[1]->getId());
-        $this->assertEquals(7, $tree[0]->getNodes()[0]->getNodes()[0]->getId());
+        $this->assertSame(1, $tree[0]->getId());
+        $this->assertSame(2, $tree[1]->getId());
+        $this->assertSame(7, $tree[0]->getNodes()[0]->getNodes()[0]->getId());
     }
 
-    public function testGetTreeViewBasic()
+    public function testGetTreeViewBasic(): void
     {
         $tree = $this->service->getTreeView(Category::class);
         $this->assertIsArray($tree);
@@ -86,30 +89,30 @@ class TreeViewGeneratorTest extends WebTestCase
         $this->assertCount(1, $tree[0]->getNodes()[0]->getNodes());
 
         //Assert that the nodes contain the correct links
-        $this->assertEquals('/en/category/1/parts', $tree[0]->getHref());
-        $this->assertEquals('/en/category/2/parts', $tree[1]->getHref());
-        $this->assertEquals('/en/category/7/parts', $tree[0]->getNodes()[0]->getNodes()[0]->getHref());
+        $this->assertSame('/en/category/1/parts', $tree[0]->getHref());
+        $this->assertSame('/en/category/2/parts', $tree[1]->getHref());
+        $this->assertSame('/en/category/7/parts', $tree[0]->getNodes()[0]->getNodes()[0]->getHref());
     }
 
-    public function testGetTreeViewNewEdit()
+    public function testGetTreeViewNewEdit(): void
     {
         $tree = $this->service->getTreeView(Category::class, null, 'newEdit');
 
         //First element should link to new category
         $this->assertStringContainsStringIgnoringCase('New', $tree[0]->getText());
-        $this->assertEquals('/en/category/new', $tree[0]->getHref());
+        $this->assertSame('/en/category/new', $tree[0]->getHref());
         //By default the new element node is selected
         $this->assertTrue($tree[0]->getState()->getSelected());
 
         //Next element is spacing
-        $this->assertEquals('', $tree[1]->getText());
+        $this->assertSame('', $tree[1]->getText());
         $this->assertTrue($tree[1]->getState()->getDisabled());
 
         //All other elements should be normal
         $this->assertCount(5, $tree);
     }
 
-    public function testGetTreeViewSelectedNode()
+    public function testGetTreeViewSelectedNode(): void
     {
         $selected = $this->em->find(Category::class, 2);
         $tree = $this->service->getTreeView(Category::class, null, 'edit', $selected);