diff --git a/Service/DependentEntity/DependentEntityService.php b/Service/DependentEntity/DependentEntityService.php
index 403d3e8..ec9a402 100644
--- a/Service/DependentEntity/DependentEntityService.php
+++ b/Service/DependentEntity/DependentEntityService.php
@@ -55,7 +55,7 @@ public function setDependentEntities(DependentEntityInterface $entity): void
                 continue;
             }
 
-            $propertyPath = $attributes[0]->getArguments()['propertypath'];
+            $propertyPath = $attributes[0]->getArguments()['propertyPath'];
 
             $propertyPathValue = $this->propertyAccessor->getValue($entity, $propertyPath);
 
diff --git a/Service/Repository/RepositoryService.php b/Service/Repository/RepositoryService.php
index fa1a884..65cf1f0 100644
--- a/Service/Repository/RepositoryService.php
+++ b/Service/Repository/RepositoryService.php
@@ -33,7 +33,7 @@ public function getEntityById(string $id, string $class): mixed
         $repository = $this->em->getRepository($class); // @phpstan-ignore-line
 
         if (!$repository instanceof GettableOneByIdInterface) {
-            throw new LogicException(\sprintf('Repository %s should implements %s interface', $repository->getClassName(), GettableOneByIdInterface::class));
+            throw new LogicException(\sprintf('Repository %s should implements %s interface', $repository::class, GettableOneByIdInterface::class));
         }
 
         return $repository->getOneById($id);
@@ -50,7 +50,7 @@ public function findEntityById(string $id, string $class): mixed
         $repository = $this->em->getRepository($class); // @phpstan-ignore-line
 
         if (!$repository instanceof FindableByIdInterface) {
-            throw new LogicException(\sprintf('Repository %s should implements %s interface', $repository->getClassName(), FindableByIdInterface::class));
+            throw new LogicException(\sprintf('Repository %s should implements %s interface', $repository::class, FindableByIdInterface::class));
         }
 
         return $repository->findOneById($id);
diff --git a/Tests/Attribute/DependentEntityTest.php b/Tests/Attribute/DependentEntityTest.php
new file mode 100644
index 0000000..dffcaf0
--- /dev/null
+++ b/Tests/Attribute/DependentEntityTest.php
@@ -0,0 +1,39 @@
+<?php
+/*
+ * This file is part of the StfalconApiBundle.
+ *
+ * (c) Stfalcon LLC <stfalcon.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace StfalconStudio\ApiBundle\Tests\Attribute;
+
+use PHPUnit\Framework\TestCase;
+use StfalconStudio\ApiBundle\Attribute\DependentEntity;
+use StfalconStudio\ApiBundle\Exception\InvalidArgumentException;
+
+/**
+ * DependedEntityTest.
+ */
+final class DependentEntityTest extends TestCase
+{
+    public function testNotEmptyPropertyPath(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('The "propertyPath" parameter can not be empty.');
+
+        new DependentEntity(propertyPath: '');
+    }
+
+    public function testGetPropertyPath(): void
+    {
+        $propertyPath = 'someField';
+        $attribute = new DependentEntity(propertyPath: $propertyPath);
+
+        self::assertSame($propertyPath, $attribute->getPropertyPath());
+    }
+}
diff --git a/Tests/Service/DependentEntity/DependentEntityServiceTest.php b/Tests/Service/DependentEntity/DependentEntityServiceTest.php
new file mode 100644
index 0000000..fe472a5
--- /dev/null
+++ b/Tests/Service/DependentEntity/DependentEntityServiceTest.php
@@ -0,0 +1,126 @@
+<?php
+/*
+ * This file is part of the StfalconApiBundle.
+ *
+ * (c) Stfalcon LLC <stfalcon.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace StfalconStudio\ApiBundle\Tests\Service\DependentEntity;
+
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use StfalconStudio\ApiBundle\Service\DependentEntity\DependentEntityService;
+use StfalconStudio\ApiBundle\Service\Repository\RepositoryService;
+use Symfony\Component\PropertyAccess\PropertyAccessor;
+
+final class DependentEntityServiceTest extends TestCase
+{
+    /** @var PropertyAccessor|MockObject */
+    private PropertyAccessor|MockObject $propertyAccessor;
+
+    /** @var RepositoryService|MockObject */
+    private RepositoryService|MockObject $repositoryService;
+
+    private DependentEntityService $dependentEntityService;
+
+    protected function setUp(): void
+    {
+        $this->repositoryService = $this->createMock(RepositoryService::class);
+        $this->propertyAccessor = $this->createMock(PropertyAccessor::class);
+        $this->dependentEntityService = new DependentEntityService($this->repositoryService);
+        $this->dependentEntityService->setPropertyAccessor($this->propertyAccessor);
+    }
+
+    protected function tearDown(): void
+    {
+        unset(
+            $this->repositoryService,
+            $this->dependentEntityService,
+            $this->propertyAccessor,
+        );
+    }
+
+    public function testSetDependentEntities(): void
+    {
+        $entity = new DummyDependentEntityClass(name: 'some name');
+
+        $dependentEntity = $this->createMock(DummyDependentEntityClass::class);
+
+        $this->propertyAccessor
+            ->expects(self::once())
+            ->method('getValue')
+            ->with($entity, 'name')
+            ->willReturn('some name')
+        ;
+
+        $this->repositoryService
+            ->expects(self::once())
+            ->method('getEntityById')
+            ->with('some name', DummyDependentEntityClass::class)
+            ->willReturn($dependentEntity)
+        ;
+
+        $this->propertyAccessor
+            ->expects(self::once())
+            ->method('setValue')
+            ->with($entity, 'dependentEntity', $dependentEntity)
+        ;
+
+        $this->dependentEntityService->setDependentEntities($entity);
+    }
+
+    public function testSetNull(): void
+    {
+        $entity = new DummyDependentEntityClass(name: 'some name');
+
+        $this->propertyAccessor
+            ->expects(self::once())
+            ->method('getValue')
+            ->with($entity, 'name')
+            ->willReturn(null)
+        ;
+
+        $this->repositoryService
+            ->expects(self::never())
+            ->method('getEntityById')
+        ;
+
+        $this->propertyAccessor
+            ->expects(self::once())
+            ->method('setValue')
+            ->with($entity, 'dependentEntity', null)
+        ;
+
+        $this->dependentEntityService->setDependentEntities($entity);
+    }
+
+    public function testEmptyAttribute(): void
+    {
+        $entity = new DummyDependentEntityClassEmptyAttribute(name: 'some name');
+
+        $this->propertyAccessor
+            ->expects(self::never())
+            ->method('getValue')
+            ->with($entity, 'name')
+            ->willReturn(null)
+        ;
+
+        $this->repositoryService
+            ->expects(self::never())
+            ->method('getEntityById')
+        ;
+
+        $this->propertyAccessor
+            ->expects(self::never())
+            ->method('setValue')
+            ->with($entity, 'dependentEntity', null)
+        ;
+
+        $this->dependentEntityService->setDependentEntities($entity);
+    }
+}
diff --git a/Tests/Service/DependentEntity/DummyDependentEntityClass.php b/Tests/Service/DependentEntity/DummyDependentEntityClass.php
new file mode 100644
index 0000000..0683232
--- /dev/null
+++ b/Tests/Service/DependentEntity/DummyDependentEntityClass.php
@@ -0,0 +1,43 @@
+<?php
+/*
+ * This file is part of the StfalconApiBundle.
+ *
+ * (c) Stfalcon LLC <stfalcon.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace StfalconStudio\ApiBundle\Tests\Service\DependentEntity;
+
+use StfalconStudio\ApiBundle\Attribute\DependentEntity;
+use StfalconStudio\ApiBundle\Service\DependentEntity\DependentEntityInterface;
+
+class DummyDependentEntityClass implements DependentEntityInterface
+{
+    #[DependentEntity(propertyPath: 'name')]
+    private ?DummyDependentEntityClass $dependentEntity;
+
+    public function __construct(private readonly string $name)
+    {
+    }
+
+    public function getName(): string
+    {
+        return $this->name;
+    }
+
+    public function getDependentEntity(): ?DummyDependentEntityClass
+    {
+        return $this->dependentEntity;
+    }
+
+    public function setDependentEntity(?DummyDependentEntityClass $dependentEntity): self
+    {
+        $this->dependentEntity = $dependentEntity;
+
+        return $this;
+    }
+}
diff --git a/Tests/Service/DependentEntity/DummyDependentEntityClassEmptyAttribute.php b/Tests/Service/DependentEntity/DummyDependentEntityClassEmptyAttribute.php
new file mode 100644
index 0000000..16759aa
--- /dev/null
+++ b/Tests/Service/DependentEntity/DummyDependentEntityClassEmptyAttribute.php
@@ -0,0 +1,41 @@
+<?php
+/*
+ * This file is part of the StfalconApiBundle.
+ *
+ * (c) Stfalcon LLC <stfalcon.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace StfalconStudio\ApiBundle\Tests\Service\DependentEntity;
+
+use StfalconStudio\ApiBundle\Service\DependentEntity\DependentEntityInterface;
+
+final class DummyDependentEntityClassEmptyAttribute implements DependentEntityInterface
+{
+    private ?DummyDependentEntityClassEmptyAttribute $dependentEntity;
+
+    public function __construct(private readonly string $name)
+    {
+    }
+
+    public function getName(): string
+    {
+        return $this->name;
+    }
+
+    public function getDependentEntity(): ?DummyDependentEntityClassEmptyAttribute
+    {
+        return $this->dependentEntity;
+    }
+
+    public function setDependentEntity(?DummyDependentEntityClassEmptyAttribute $dependentEntity): self
+    {
+        $this->dependentEntity = $dependentEntity;
+
+        return $this;
+    }
+}
diff --git a/Tests/Service/Repository/DummyRepository.php b/Tests/Service/Repository/DummyRepository.php
new file mode 100644
index 0000000..7e53aaf
--- /dev/null
+++ b/Tests/Service/Repository/DummyRepository.php
@@ -0,0 +1,29 @@
+<?php
+/*
+ * This file is part of the StfalconApiBundle.
+ *
+ * (c) Stfalcon LLC <stfalcon.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace StfalconStudio\ApiBundle\Tests\Service\Repository;
+
+use StfalconStudio\ApiBundle\Service\Repository\FindableByIdInterface;
+use StfalconStudio\ApiBundle\Service\Repository\GettableOneByIdInterface;
+
+class DummyRepository implements GettableOneByIdInterface, FindableByIdInterface
+{
+    public function findOneById(string $id): mixed
+    {
+        return null;
+    }
+
+    public function getOneById(string $id): mixed
+    {
+        return null;
+    }
+}
diff --git a/Tests/Service/Repository/DummyRepositoryWithOutInterface.php b/Tests/Service/Repository/DummyRepositoryWithOutInterface.php
new file mode 100644
index 0000000..1677bca
--- /dev/null
+++ b/Tests/Service/Repository/DummyRepositoryWithOutInterface.php
@@ -0,0 +1,17 @@
+<?php
+/*
+ * This file is part of the StfalconApiBundle.
+ *
+ * (c) Stfalcon LLC <stfalcon.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace StfalconStudio\ApiBundle\Tests\Service\Repository;
+
+class DummyRepositoryWithOutInterface
+{
+}
diff --git a/Tests/Service/Repository/RepositoryServiceTest.php b/Tests/Service/Repository/RepositoryServiceTest.php
new file mode 100644
index 0000000..55f29e7
--- /dev/null
+++ b/Tests/Service/Repository/RepositoryServiceTest.php
@@ -0,0 +1,130 @@
+<?php
+/*
+ * This file is part of the StfalconApiBundle.
+ *
+ * (c) Stfalcon LLC <stfalcon.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace StfalconStudio\ApiBundle\Tests\Service\Repository;
+
+use Doctrine\ORM\EntityManager;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+use StfalconStudio\ApiBundle\Exception\LogicException;
+use StfalconStudio\ApiBundle\Service\Repository\RepositoryService;
+
+final class RepositoryServiceTest extends TestCase
+{
+    /** @var EntityManager|MockObject */
+    private EntityManager|MockObject $entityManager;
+
+    private RepositoryService $repositoryService;
+
+    protected function setUp(): void
+    {
+        $this->entityManager = $this->createMock(EntityManager::class);
+        $this->repositoryService = new RepositoryService();
+        $this->repositoryService->setEntityManager($this->entityManager);
+    }
+
+    protected function tearDown(): void
+    {
+        unset(
+            $this->repositoryService,
+            $this->entityManager,
+        );
+    }
+
+    public function testGetEntityById(): void
+    {
+        $id = '123';
+        $class = 'someClassName';
+        $repository = $this->createMock(DummyRepository::class);
+
+        $entity = new \stdClass();
+
+        $this->entityManager
+            ->expects(self::once())
+            ->method('getRepository')
+            ->with($class)
+            ->willReturn($repository)
+        ;
+
+        $repository
+            ->expects(self::once())
+            ->method('getOneById')
+            ->with($id)
+            ->willReturn($entity)
+        ;
+
+        $result = $this->repositoryService->getEntityById($id, $class);
+        self::assertSame($result, $entity);
+    }
+
+    public function testFindEntityById(): void
+    {
+        $id = '123';
+        $class = 'someClassName';
+        $repository = $this->createMock(DummyRepository::class);
+
+        $entity = new \stdClass();
+
+        $this->entityManager
+            ->expects(self::once())
+            ->method('getRepository')
+            ->with($class)
+            ->willReturn($repository)
+        ;
+
+        $repository
+            ->expects(self::once())
+            ->method('findOneById')
+            ->with($id)
+            ->willReturn($entity)
+        ;
+
+        $result = $this->repositoryService->findEntityById($id, $class);
+        self::assertSame($result, $entity);
+    }
+
+    public function testGetEntityByIdException(): void
+    {
+        $id = '123';
+        $class = 'someClassName';
+        $repository = $this->createMock(DummyRepositoryWithOutInterface::class);
+
+        $this->entityManager
+            ->expects(self::once())
+            ->method('getRepository')
+            ->with($class)
+            ->willReturn($repository)
+        ;
+
+        $this->expectException(LogicException::class);
+
+        $this->repositoryService->getEntityById($id, $class);
+    }
+
+    public function testFindEntityByIdException(): void
+    {
+        $id = '123';
+        $class = 'someClassName';
+        $repository = $this->createMock(DummyRepositoryWithOutInterface::class);
+
+        $this->entityManager
+            ->expects(self::once())
+            ->method('getRepository')
+            ->with($class)
+            ->willReturn($repository)
+        ;
+
+        $this->expectException(LogicException::class);
+
+        $this->repositoryService->findEntityById($id, $class);
+    }
+}