diff --git a/core/tests/Drupal/Tests/Core/DependencyInjection/ContainerBuilderTest.php b/core/tests/Drupal/Tests/Core/DependencyInjection/ContainerBuilderTest.php
index f2537c8..fc97787 100644
--- a/core/tests/Drupal/Tests/Core/DependencyInjection/ContainerBuilderTest.php
+++ b/core/tests/Drupal/Tests/Core/DependencyInjection/ContainerBuilderTest.php
@@ -9,10 +9,9 @@
 
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Tests\UnitTestCase;
+use Drupal\Tests\Core\DependencyInjection\Fixture\BazClass;
+use Drupal\Tests\Core\DependencyInjection\Fixture\BarClass;
 use Symfony\Component\DependencyInjection\Reference;
-use Symfony\Component\Routing\Tests\Fixtures\AnnotatedClasses\BarClass;
-
-require_once __DIR__ . '../../../../../../vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Tests/Fixtures/includes/classes.php';
 
 /**
  * @coversDefaultClass \Drupal\Core\DependencyInjection\ContainerBuilder
@@ -22,40 +21,38 @@ class ContainerBuilderTest extends UnitTestCase {
 
   /**
    * Tests set with a synchronized service.
+   *
+   * @covers ::set
    */
   public function testSetOnSynchronizedService() {
     $container = new ContainerBuilder();
-    $container->register('baz', 'BazClass')
+    $container->register('baz', '\Drupal\Tests\Core\DependencyInjection\Fixture\BazClass')
       ->setSynchronized(TRUE);
-    $container->register('bar', 'BarClass')
+    $container->register('bar', '\Drupal\Tests\Core\DependencyInjection\Fixture\BarClass')
       ->addMethodCall('setBaz', array(new Reference('baz')));
 
     // Ensure that we can set services on a compiled container.
     $container->compile();
 
-    $container->set('baz', $baz = new \BazClass());
+    $container->set('baz', $baz = new BazClass());
     $this->assertSame($baz, $container->get('bar')->getBaz());
 
-    $container->set('baz', $baz = new \BazClass());
+    $container->set('baz', $baz = new BazClass());
     $this->assertSame($baz, $container->get('bar')->getBaz());
   }
 
   /**
-   * Tests the get method.
-   *
-   * @see \Drupal\Core\DependencyInjection\Container::get()
+   * @covers ::get
    */
   public function testGet() {
     $container = new ContainerBuilder();
-    $container->register('bar', 'BarClass');
+    $container->register('bar', 'Drupal\Tests\Core\DependencyInjection\Fixture\BarClass');
 
     $result = $container->get('bar');
-    $this->assertTrue($result instanceof \BarClass);
+    $this->assertTrue($result instanceof BarClass);
   }
 
   /**
-   * Tests the set() method.
-   *
    * @covers ::set
    */
   public function testSet() {
diff --git a/core/tests/Drupal/Tests/Core/DependencyInjection/ContainerTest.php b/core/tests/Drupal/Tests/Core/DependencyInjection/ContainerTest.php
index 5c73281..377f7be 100644
--- a/core/tests/Drupal/Tests/Core/DependencyInjection/ContainerTest.php
+++ b/core/tests/Drupal/Tests/Core/DependencyInjection/ContainerTest.php
@@ -9,7 +9,7 @@
 
 use Drupal\Core\DependencyInjection\Container;
 use Drupal\Tests\UnitTestCase;
-use Symfony\Component\Routing\Tests\Fixtures\AnnotatedClasses\BarClass;
+use Drupal\Tests\Core\DependencyInjection\Fixture\BarClass;
 
 /**
  * @coversDefaultClass \Drupal\Core\DependencyInjection\Container
@@ -18,36 +18,23 @@
 class ContainerTest extends UnitTestCase {
 
   /**
-   * The tested container.
-   *
-   * @var \Drupal\Core\DependencyInjection\Container
-   */
-  public $container;
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    $this->container = new Container();
-  }
-
-  /**
    * Tests serialization.
    *
    * @expectedException \PHPUnit_Framework_Error
    */
   public function testSerialize() {
-    serialize($this->container);
+    $container = new Container();
+    serialize($container);
   }
 
   /**
-   * Tests the set() method.
-   *
    * @covers ::set
    */
   public function testSet() {
+    $container = new Container();
     $class = new BarClass();
-    $this->container->set('bar', $class);
+    $container->set('bar', $class);
+    // Ensure that _serviceId is set on the object.
     $this->assertEquals('bar', $class->_serviceId);
   }
 
diff --git a/core/tests/Drupal/Tests/Core/DependencyInjection/Fixture/BarClass.php b/core/tests/Drupal/Tests/Core/DependencyInjection/Fixture/BarClass.php
new file mode 100644
index 0000000..bec5d88
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/DependencyInjection/Fixture/BarClass.php
@@ -0,0 +1,47 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\DependencyInjection\Fixture\BarClass.
+ */
+
+namespace Drupal\Tests\Core\DependencyInjection\Fixture;
+
+/**
+ * Stub class which acts as a service to test the container.
+ *
+ * @see \Drupal\Tests\Core\DependencyInjection\ContainerBuilderTest
+ * @see \Drupal\Tests\Core\DependencyInjection\Fixture\BazClass
+ */
+class BarClass {
+
+  /**
+   * Storage for a protected BazClass object.
+   *
+   * @var Drupal\Tests\Core\DependencyInjection\Fixture\BazClass
+   */
+  protected $baz;
+
+  /**
+   * Setter for our BazClass object.
+   *
+   * This method is called during the service initialization.
+   *
+   * @param \Drupal\Tests\Core\DependencyInjection\Fixture\BazClass $baz
+   *   A BazClass object to store.
+   */
+  public function setBaz(BazClass $baz) {
+    $this->baz = $baz;
+  }
+
+  /**
+   * Getter for our BazClass object.
+   *
+   * @return \Drupal\Tests\Core\DependencyInjection\Fixture\BazClass
+   *   The stored BazClass object.
+   */
+  public function getBaz() {
+    return $this->baz;
+  }
+
+}
diff --git a/core/tests/Drupal/Tests/Core/DependencyInjection/Fixture/BazClass.php b/core/tests/Drupal/Tests/Core/DependencyInjection/Fixture/BazClass.php
new file mode 100644
index 0000000..361b4a8
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/DependencyInjection/Fixture/BazClass.php
@@ -0,0 +1,18 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\DependencyInjection\Fixture\BazClass.
+ */
+
+namespace Drupal\Tests\Core\DependencyInjection\Fixture;
+
+/**
+ * Stub class which acts as a service dependency, to test the container.
+ *
+ * @see \Drupal\Tests\Core\DependencyInjection\ContainerBuilderTest
+ * @see \Drupal\Tests\Core\DependencyInjection\Fixture\BarClass
+ */
+class BazClass {
+
+}