diff --git a/core/modules/system/src/Tests/Theme/ImageTest.php b/core/modules/system/src/Tests/Theme/ImageTest.php
index f37ef9b..5563c0f 100644
--- a/core/modules/system/src/Tests/Theme/ImageTest.php
+++ b/core/modules/system/src/Tests/Theme/ImageTest.php
@@ -33,14 +33,13 @@ class ImageTest extends DrupalUnitTestBase {
   protected function setUp() {
     parent::setUp();
     $this->testImages = array(
-      DRUPAL_ROOT . '/core/misc/druplicon.png',
-      DRUPAL_ROOT . '/core/misc/loading.gif',
-      DRUPAL_ROOT . '/core/misc/loading-small.gif',
+      '/core/misc/druplicon.png',
+      '/core/misc/loading.gif',
     );
   }
 
   /**
-   * Tests that an image with the src attribute is outputted correctly.
+   * Tests that an image with the src attribute is output correctly.
    */
   function testThemeImageWithSrc() {
 
@@ -49,21 +48,20 @@ function testThemeImageWithSrc() {
       '#uri' => reset($this->testImages),
       '#width' => rand(0, 1000) . 'px',
       '#height' => rand(0, 500) . 'px',
-      '#alt' => $this->randomString(),
-      '#title' => $this->randomString(),
+      '#alt' => $this->randomMachineName(),
+      '#title' => $this->randomMachineName(),
     );
     $this->render($image);
     $this->removeWhiteSpace();
-    $expected = '<img src="' . $image['#uri'] . '" width="' . $image['#width']
-      . '" height="' . $image['#height'] . '" alt="' . $image['#alt']
-      . '" title="' . $image['#title'] . '" />';
+    $expected = '<img src="' . file_create_url($image['#uri']) . '" ' . 'width="' . $image['#width'] . '" '
+      . 'height="' . $image['#height'] . '" alt="' . $image['#alt'] . '" title="' . $image['#title'] . '" />';
     $this->assertRaw($expected, 'Correct output for image with src attribute.');
   }
 
   /**
-   * Tests that an image with the srcset attribute is outputted correctly.
+   * Tests that an image with the srcset and multipliers is output correctly.
    */
-  function testThemeImageWithSrcset() {
+  function testThemeImageWithSrcsetMultiplier() {
     // Test with multipliers.
     $image = array(
       '#theme' => 'image',
@@ -76,23 +74,50 @@ function testThemeImageWithSrcset() {
           'uri' => $this->testImages[1],
           'multiplier' => '2x',
         ),
+      ),
+      '#width' => rand(0, 1000) . 'px',
+      '#height' => rand(0, 500) . 'px',
+      '#alt' => $this->randomMachineName(),
+      '#title' => $this->randomMachineName(),
+    );
+    $this->render($image);
+    $this->removeWhiteSpace();
+    $expected = '<img srcset="' . file_create_url($this->testImages[0]) . ' 1x, ' . file_create_url($this->testImages[1]) . ' 2x" '
+      . 'width="' . $image['#width'] . '" height="' . $image['#height'] . '" alt="' . $image['#alt'] . '" title="' . $image['#title'] . '" />';
+    $this->assertRaw($expected, 'Correct output for image with srcset attribute and multipliers.');
+  }
+
+  /**
+   * Tests that an image with the srcset and widths is output correctly.
+   */
+  function testThemeImageWithSrcsetWidth() {
+    // Test with multipliers.
+    $widths = array(
+      rand(0, 500) . 'w',
+      rand(500, 1000) . 'w',
+    );
+    $image = array(
+      '#theme' => 'image',
+      '#srcset' => array(
         array(
-          'uri' => $this->testImages[2],
-          'width' => '640w',
+          'uri' => $this->testImages[0],
+          'width' => $widths[0],
+        ),
+        array(
+          'uri' => $this->testImages[1],
+          'width' => $widths[1],
         ),
       ),
       '#width' => rand(0, 1000) . 'px',
       '#height' => rand(0, 500) . 'px',
-      '#alt' => $this->randomString(),
-      '#title' => $this->randomString(),
+      '#alt' => $this->randomMachineName(),
+      '#title' => $this->randomMachineName(),
     );
     $this->render($image);
     $this->removeWhiteSpace();
-    $expected = '<img srcset="' . $this->testImages[0] . ' 1x, '
-      . $this->testImages[1] . ' 2x, ' . $this->testImages[2] . ' 640w" width="'
-      . $image['#width'] . '" height="' . $image['#height'] . '" alt="'
-      . $image['#alt'] . '" title="' . $image['#title'] . '" />';
-    $this->assertRaw($expected, 'Correct output for image with srcset attribute.');
+    $expected = '<img srcset="' . file_create_url($this->testImages[0]) . ' ' . $widths[0] . ', ' . file_create_url($this->testImages[1]) . ' ' . $widths[1] . '" '
+      . 'width="' . $image['#width'] . '" height="' . $image['#height'] . '" alt="' . $image['#alt'] . '" title="' . $image['#title'] . '" />';
+    $this->assertRaw($expected, 'Correct output for image with srcset attribute and width descriptors.');
   }
 
 }