diff --git a/core/tests/Drupal/Tests/Core/Routing/CachedUrlGeneratorTest.php b/core/tests/Drupal/Tests/Core/Routing/CachedUrlGeneratorTest.php
index 42dd4de..27c262d 100644
--- a/core/tests/Drupal/Tests/Core/Routing/CachedUrlGeneratorTest.php
+++ b/core/tests/Drupal/Tests/Core/Routing/CachedUrlGeneratorTest.php
@@ -9,10 +9,13 @@
 
 use Drupal\Core\Routing\CachedUrlGenerator;
 use Drupal\Tests\UnitTestCase;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\RequestStack;
 
 /**
  * Tests the cache url generator.
  *
+ * @coversDefaultClass \Drupal\Core\Routing\CachedUrlGenerator
  * @group Routing
  */
 class CachedUrlGeneratorTest extends UnitTestCase {
@@ -60,6 +63,13 @@ class CachedUrlGeneratorTest extends UnitTestCase {
   protected $route;
 
   /**
+   * The log of all caches accessed. Keyed by cid.
+   *
+   * $var array
+   */
+  protected $cacheIds = array();
+
+  /**
    * {@inheritdoc}
    */
   protected function setUp() {
@@ -181,5 +191,66 @@ public function testGenerateFromRouteWithDifferentParameters() {
     $this->assertEquals('http://localhost/test-route-1/value2', $this->cachedUrlGenerator->generateFromRoute('test_route', array('key' => 'value2'), array('absolute' => TRUE)));
   }
 
+  /**
+   * Tests that prepareCache's treatment of routes is case sensitive.
+   * i.e. Different caches are accessed for similar but distinctly named
+   * requests.
+   *
+   * For example, these URLs
+   *
+   * "/PAGE/A"
+   * "/PAGE/a"
+   *
+   * are not the same and that when processing the request the accumulation of
+   * generated URLs should be cached separately.
+   *
+   * @covers \Drupal\Core\Routing\CachedUrlGenerator::prepareCache()
+   */
+  public function testPrepareCache(){
+
+    // Attach a monitor to capture the number of unique caches accessed.
+    $this->cache->expects($this->any())
+      ->method('set')
+      ->will($this->returnCallback(array($this, 'logCacheIdentifiers')));
+
+    $requestStack = new RequestStack();
+
+    // For a lowercase request populate the array of URLs and then cache it.
+    $request1 = Request::create('/page/a');
+    $request1->attributes->set('_system_path', '/page/a');
+    $requestStack->push($request1);
+    $this->cachedUrlGenerator->prepareCache($requestStack);
+    $this->cachedUrlGenerator->generateFromRoute('test-route-1');
+    $this->cachedUrlGenerator->destruct(); // write to cache
+
+    // For a uppercase request populate the array of URLs and then cache it.
+    $request2 = Request::create('/PAGE/A');
+    $request2->attributes->set('_system_path', '/PAGE/A');
+    $requestStack->push($request2);
+    $this->cachedUrlGenerator->prepareCache($requestStack);
+    $this->cachedUrlGenerator->generateFromRoute('test-route-1');
+    $this->cachedUrlGenerator->destruct(); // write to cache.
+
+    // Verify that two uniquely named caches have been accessed - One for each request.
+    $this->assertEquals(count($this->cacheIds), 2, 'Two unique caches have been stored.');
+  }
+
+  /**
+   * Monitor the number of distinct caches that are accessed.
+   *
+   * Build up a list of unique cache identifiers as access to them is sought.
+   *
+   * The form of the set method being mocked :-
+   *
+   *  set($cid, $data, $expire = Cache::PERMANENT, array $tags = array());
+   */
+  public function logCacheIdentifiers() {
+    $arg = func_get_args();
+
+    // cid is insensitive to the case of the identifier.
+    $cid = strtolower($arg[0]);
+
+    $this->cacheIds[$cid] = 1;
+  }
 }