diff --git a/core/tests/Drupal/Tests/Standards/DrupalStandardsListener.php b/core/tests/Drupal/Tests/Standards/DrupalStandardsListener.php
index 59b2016..353d6ca 100644
--- a/core/tests/Drupal/Tests/Standards/DrupalStandardsListener.php
+++ b/core/tests/Drupal/Tests/Standards/DrupalStandardsListener.php
@@ -16,6 +16,13 @@
 class DrupalStandardsListener extends \PHPUnit_Framework_BaseTestListener {
 
   /**
+   * Saves the classes that fail the namespace check.
+   *
+   * @var array
+   */
+  protected $namespaceCheckFailedClasses = array();
+
+  /**
    * Signals a coding standards failure to the user.
    *
    * @param \PHPUnit_Framework_TestCase $test
@@ -144,6 +151,24 @@ public function checkValidCoversForTest(\PHPUnit_Framework_TestCase $test) {
   }
 
   /**
+   * Checks that tests are in the Drupal\Tests namespace. 
+   *
+   * @param \PHPUnit_Framework_Test $test
+   *   The test where we should insert our test failure.
+   */
+  protected function checkValidNamespaceForTest(\PHPUnit_Framework_Test $test) {
+    $class = get_class($test);
+    if (!in_array($class, $this->namespaceCheckFailedClasses) && strpos($class, 'Drupal\Tests\\', 0) !== 0) {
+      // For the unit test of this method we run endTest() twice, but we don't
+      // want to run this namespace check a second time as the test failure
+      // would go uncaught.
+      $this->namespaceCheckFailedClasses[] = $class;
+      $test->assertTrue(FALSE, 'Test is not in the Drupal\Tests namespace.');
+    }
+  }
+
+
+  /**
    * {@inheritdoc}
    */
   public function endTest(\PHPUnit_Framework_Test $test, $time) {
@@ -152,6 +177,7 @@ public function endTest(\PHPUnit_Framework_Test $test, $time) {
     // subclasses.
     if ($test instanceof \PHPUnit_Framework_TestCase) {
       $this->checkValidCoversForTest($test);
+      $this->checkValidNamespaceForTest($test);
     }
     elseif ($test instanceof \PHPUnit_Framework_TestSuite) {
       foreach ($test->getGroupDetails() as $tests) {
diff --git a/core/tests/bootstrap.php b/core/tests/bootstrap.php
index d0512e1..a434d16 100644
--- a/core/tests/bootstrap.php
+++ b/core/tests/bootstrap.php
@@ -70,6 +70,7 @@ function drupal_phpunit_register_extension_dirs(Composer\Autoload\ClassLoader $l
 // Start with classes in known locations.
 $loader = require __DIR__ . '/../../autoload.php';
 $loader->add('Drupal\\Tests', __DIR__);
+$loader->add('Drupal\\DrupalStandardsListenerTest', __DIR__);
 
 // Scan for arbitrary extension namespaces from core and contrib.
 $extension_roots = array_merge(array(