diff --git a/core/lib/Drupal/Core/Routing/CachedUrlGenerator.php b/core/lib/Drupal/Core/Routing/CachedUrlGenerator.php
index d6c5745..4ba98cb 100644
--- a/core/lib/Drupal/Core/Routing/CachedUrlGenerator.php
+++ b/core/lib/Drupal/Core/Routing/CachedUrlGenerator.php
@@ -139,7 +139,7 @@ public function generate($name, $parameters = array(), $absolute = FALSE) {
    * {@inheritdoc}
    */
   public function generateFromPath($path = NULL, $options = array()) {
-    $key = self::PATH_CACHE_PREFIX . hash('sha256', $path . serialize($options));
+    $key = static::PATH_CACHE_PREFIX . hash('sha256', $path . serialize($options));
     if (!isset($this->cachedUrls[$key])) {
       $this->cachedUrls[$key] = $this->urlGenerator->generateFromPath($path, $options);
       $this->cacheNeedsWriting = TRUE;
@@ -152,7 +152,7 @@ public function generateFromPath($path = NULL, $options = array()) {
    */
   public function generateFromRoute($name, $parameters = array(), $options = array()) {
     // In some cases $name may be a Route object, rather than a string.
-    $key = self::ROUTE_CACHE_PREFIX . hash('sha256', serialize($name) . serialize($options) . serialize($parameters));
+    $key = static::ROUTE_CACHE_PREFIX . hash('sha256', serialize($name) . serialize($options) . serialize($parameters));
     if (!isset($this->cachedUrls[$key])) {
       $generated_url = $this->urlGenerator->generateFromRoute($name, $parameters, $options);
       $route = $this->getRoute($name);
diff --git a/core/tests/Drupal/Tests/Core/Routing/CachedUrlGeneratorTest.php b/core/tests/Drupal/Tests/Core/Routing/CachedUrlGeneratorTest.php
index 7fa538b..6242bb6 100644
--- a/core/tests/Drupal/Tests/Core/Routing/CachedUrlGeneratorTest.php
+++ b/core/tests/Drupal/Tests/Core/Routing/CachedUrlGeneratorTest.php
@@ -21,7 +21,7 @@
 class CachedUrlGeneratorTest extends UnitTestCase {
 
   /**
-   * The wrapped url generator.
+   * The wrapped URL generator.
    *
    * @var \Drupal\Core\Routing\UrlGeneratorInterface|\PHPUnit_Framework_MockObject_MockObject
    */
@@ -63,7 +63,7 @@ class CachedUrlGeneratorTest extends UnitTestCase {
   protected $route;
 
   /**
-   *The request stack.
+   * The request stack.
    *
    * @var \Symfony\Component\HttpFoundation\RequestStack
    */
@@ -99,8 +99,9 @@ public function testGenerate() {
       ->method('generateFromRoute')
       ->with('test_route')
       ->will($this->returnValue('test-route-1'));
+    // First call will prime the cache.
     $this->assertEquals('test-route-1', $this->cachedUrlGenerator->generateFromRoute('test_route'));
-    // Second call will fetch from cache.
+    // Second call will fetch from the cache.
     $this->assertEquals('test-route-1', $this->cachedUrlGenerator->generateFromRoute('test_route'));
   }
 
@@ -110,19 +111,24 @@ public function testGenerate() {
    * @see \Drupal\Core\Routing\CachedUrlGenerator::generate()
    */
   public function testGenerateWithDifferentParameters() {
+    // We are generating URL's four times but since two of them are cached,
+    // we expect that generateFromRoute will only be called twice.
     $this->urlGenerator->expects($this->exactly(2))
       ->method('generateFromRoute')
       ->will($this->returnValueMap(array(
         array('test_route', array('key' => 'value1'), array(), 'test-route-1/value1'),
         array('test_route', array('key' => 'value2'), array(), 'test-route-1/value2'),
       )));
+
+    // First call will prime the cache for key=value1.
     $this->assertEquals('test-route-1/value1', $this->cachedUrlGenerator->generate('test_route', array('key' => 'value1')));
-    // Second call will fetch from cache.
+    // Second call will fetch from the cache.
     $this->assertEquals('test-route-1/value1', $this->cachedUrlGenerator->generate('test_route', array('key' => 'value1')));
-    // Third call uses the same route with different parameters, so will call
-    // into the UrlGenerator mock.
+    // Third call uses the same route but since the parameters are different,
+    // the cache is not used and the generateFromRoute method will be called
+    // for the second time.
     $this->assertEquals('test-route-1/value2', $this->cachedUrlGenerator->generate('test_route', array('key' => 'value2')));
-    // Fourth call will fetch from cache.
+    // Fourth call will fetch from the cache as it is now primed.
     $this->assertEquals('test-route-1/value2', $this->cachedUrlGenerator->generate('test_route', array('key' => 'value2')));
   }
 
@@ -136,8 +142,10 @@ public function testGenerateFromPath() {
       ->method('generateFromPath')
       ->with('test-route-1')
       ->will($this->returnValue('test-route-1'));
+
+    // First call will prime the cache.
     $this->assertEquals('test-route-1', $this->cachedUrlGenerator->generateFromPath('test-route-1'));
-    // Second call will fetch from cache.
+    // Second call will fetch from the cache.
     $this->assertEquals('test-route-1', $this->cachedUrlGenerator->generateFromPath('test-route-1'));
   }
 
@@ -147,17 +155,22 @@ public function testGenerateFromPath() {
    * @see \Drupal\Core\Routing\CachedUrlGenerator::generateFromPath()
    */
   public function testGenerateFromPathWithDifferentParameters() {
+    // We are generating URL's four times but since two of them are cached,
+    // we expect that generateFromPath will only be called twice.
     $this->urlGenerator->expects($this->exactly(2))
       ->method('generateFromPath')
       ->will($this->returnValueMap(array(
         array('test-route-1', array('absolute' => TRUE), 'http://localhost/test-route-1'),
         array('test-route-1', array('absolute' => FALSE), 'test-route-1'),
       )));
+
+    // First call will prime the cache.
     $this->assertEquals('http://localhost/test-route-1', $this->cachedUrlGenerator->generateFromPath('test-route-1', array('absolute' => TRUE)));
     // Second call will fetch from cache.
     $this->assertEquals('http://localhost/test-route-1', $this->cachedUrlGenerator->generateFromPath('test-route-1', array('absolute' => TRUE)));
-    // Third call uses the same route, with different parameters, so will call
-    // into the UrlGenerator mock.
+    // Third call uses the same path but since the options are different, the
+    // cache is not used and the generateFromPath method will be called for
+    // the second time.
     $this->assertEquals('test-route-1', $this->cachedUrlGenerator->generateFromPath('test-route-1', array('absolute' => FALSE)));
     // Fourth call will fetch from cache.
     $this->assertEquals('test-route-1', $this->cachedUrlGenerator->generateFromPath('test-route-1', array('absolute' => FALSE)));
@@ -174,8 +187,10 @@ public function testGenerateFromRoute() {
       ->method('generateFromRoute')
       ->with('test_route')
       ->will($this->returnValue('test-route-1'));
+
+    // First call will prime the cache.
     $this->assertEquals('test-route-1', $this->cachedUrlGenerator->generateFromRoute('test_route'));
-    // Second call will fetch from cache.
+    // Second call will fetch from the cache.
     $this->assertEquals('test-route-1', $this->cachedUrlGenerator->generateFromRoute('test_route'));
   }
 
@@ -185,6 +200,8 @@ public function testGenerateFromRoute() {
    * @see \Drupal\Core\Routing\CachedUrlGenerator::generateFromRoute()
    */
   public function testGenerateFromRouteWithDifferentParameters() {
+    // We are generating URL's eight times but since two of them are cached,
+    // we expect that generateFromRoute will only be called four times.
     $this->urlGenerator->expects($this->exactly(4))
       ->method('generateFromRoute')
       ->will($this->returnValueMap(array(
@@ -193,23 +210,28 @@ public function testGenerateFromRouteWithDifferentParameters() {
         array('test_route', array('key' => 'value2'), array(), 'test-route-1/value2'),
         array('test_route', array('key' => 'value2'), array('absolute' => TRUE), 'http://localhost/test-route-1/value2'),
       )));
+
+    // First call will prime the cache.
     $this->assertEquals('test-route-1/value1', $this->cachedUrlGenerator->generateFromRoute('test_route', array('key' => 'value1')));
-    // Second call will fetch from cache.
+    // Second call will fetch from the cache.
     $this->assertEquals('test-route-1/value1', $this->cachedUrlGenerator->generateFromRoute('test_route', array('key' => 'value1')));
-    // Third call uses the same route, with different parameters, so will call
-    // into the UrlGenerator mock.
+    // Third call uses the same route but since the options are different, the
+    // cache is not used and the generateFromRoute method will be called for
+    // the second time.
     $this->assertEquals('http://localhost/test-route-1/value1', $this->cachedUrlGenerator->generateFromRoute('test_route', array('key' => 'value1'), array('absolute' => TRUE)));
-    // Fourth call will fetch form cache.
+    // Fourth call will fetch from the cache.
     $this->assertEquals('http://localhost/test-route-1/value1', $this->cachedUrlGenerator->generateFromRoute('test_route', array('key' => 'value1'), array('absolute' => TRUE)));
-    // Fifth call uses the same route, with different parameters, so will call
-    // into the UrlGenerator mock.
+    // Fifth call uses the same route but since the parameters are different,
+    // the cache is not used and the generateFromRoute method will be called for
+    // the third time.
     $this->assertEquals('test-route-1/value2', $this->cachedUrlGenerator->generateFromRoute('test_route', array('key' => 'value2')));
-    // Sixth call will fetch from cache.
+    // Sixth call will fetch from the cache.
     $this->assertEquals('test-route-1/value2', $this->cachedUrlGenerator->generateFromRoute('test_route', array('key' => 'value2')));
-    // Seventh call uses the same route, with different parameters, so will call
-    // into the UrlGenerator mock.
+    // Seventh call uses the same route but since the options are different, the
+    // cache is not used and the generateFromRoute method will be called for
+    // the fourth time.
     $this->assertEquals('http://localhost/test-route-1/value2', $this->cachedUrlGenerator->generateFromRoute('test_route', array('key' => 'value2'), array('absolute' => TRUE)));
-    // Eighth call will fetch from cache.
+    // Eighth call will fetch from the cache.
     $this->assertEquals('http://localhost/test-route-1/value2', $this->cachedUrlGenerator->generateFromRoute('test_route', array('key' => 'value2'), array('absolute' => TRUE)));
   }