diff --git a/core/modules/image/src/Tests/ImageStyleTest.php b/core/modules/image/src/Tests/ImageStyleTest.php
index 2628485..b00c724 100644
--- a/core/modules/image/src/Tests/ImageStyleTest.php
+++ b/core/modules/image/src/Tests/ImageStyleTest.php
@@ -69,8 +69,8 @@ public static function getInfo() {
    * {@inheritdoc}
    */
   public function setUp() {
-    $this->entityTypeId = $this->randomName();
-    $this->provider = $this->randomName();
+    $this->entityTypeId = $this->randomMachineName();
+    $this->provider = $this->randomMachineName();
     $this->entityType = $this->getMock('\Drupal\Core\Entity\EntityTypeInterface');
     $this->entityType->expects($this->any())
                      ->method('getProvider')
@@ -91,7 +91,7 @@ public function setUp() {
    * @covers ::transformMimeType
    */
   public function testTransformMimeType() {
-    $image_effect_id = $this->randomName();
+    $image_effect_id = $this->randomMachineName();
     $image_effect = $this->getMockBuilder('\Drupal\image\ImageEffectBase')
         ->setConstructorArgs(array(array(), $image_effect_id, array()))
         ->getMock();
diff --git a/core/modules/responsive_image/tests/src/ResponsiveImageMappingConfigEntityUnitTest.php b/core/modules/responsive_image/tests/src/ResponsiveImageMappingConfigEntityUnitTest.php
index 169ed6e..9b18e11 100644
--- a/core/modules/responsive_image/tests/src/ResponsiveImageMappingConfigEntityUnitTest.php
+++ b/core/modules/responsive_image/tests/src/ResponsiveImageMappingConfigEntityUnitTest.php
@@ -132,13 +132,26 @@ public function testHasMappings() {
 
   /**
    * @covers ::addMapping
-   * @covers ::getImageStyle
+   * @covers ::getMappingDefinition
    */
-  public function testGetImageStyle() {
+  public function testGetMappingDefinition() {
     $entity = new ResponsiveImageMapping(array(''));
-    $entity->addMapping('test_breakpoint', '1x', 'test_style');
-    $this->assertEquals('test_style', $entity->getImageStyle('test_breakpoint', '1x'));
-    $this->assertNull($entity->getImageStyle('test_unknown_breakpoint', '1x'));
+    $entity->addMapping('test_breakpoint', '1x',  array(
+        'mapping_type' => 'image_style',
+        'image_style' => 'large',
+        'sizes' => '',
+        'sizes_image_styles' => array(),
+    ));
+    $expected = array(
+      'breakpoint_id' => 'test_breakpoint',
+      'multiplier' => '1x',
+      'mapping_type' => 'image_style',
+      'image_style' => 'large',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    );
+    $this->assertEquals($expected, $entity->getMappingDefinition('test_breakpoint', '1x'));
+    $this->assertNull($entity->getMappingDefinition('test_unknown_breakpoint', '1x'));
   }
 
   /**
@@ -147,24 +160,76 @@ public function testGetImageStyle() {
    */
   public function testGetKeyedMappings() {
     $entity = new ResponsiveImageMapping(array(''));
-    $entity->addMapping('test_breakpoint', '1x', 'test_style');
-    $entity->addMapping('test_breakpoint', '2x', 'test_style2');
-    $entity->addMapping('test_breakpoint2', '1x', 'test_style3');
+    $entity->addMapping('test_breakpoint', '1x', array(
+      'mapping_type' => 'image_style',
+      'image_style' => 'large',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    ));
+    $entity->addMapping('test_breakpoint', '2x', array(
+      'mapping_type' => 'sizes',
+      'image_style' => '',
+      'sizes' => '(min-width:700px) 700px, 100vw',
+      'sizes_image_styles' => array(
+        'large' => 'large',
+      ),
+    ));
+    $entity->addMapping('test_breakpoint2', '1x',  array(
+      'mapping_type' => 'image_style',
+      'image_style' => 'thumbnail',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    ));
 
     $expected = array(
       'test_breakpoint' => array(
-        '1x' => 'test_style',
-        '2x' => 'test_style2',
+        '1x' => array(
+          'breakpoint_id' => 'test_breakpoint',
+          'multiplier' => '1x',
+          'mapping_type' => 'image_style',
+          'image_style' => 'large',
+          'sizes' => '',
+          'sizes_image_styles' => array(),
+        ),
+        '2x' => array(
+          'breakpoint_id' => 'test_breakpoint',
+          'multiplier' => '2x',
+          'mapping_type' => 'sizes',
+          'image_style' => '',
+          'sizes' => '(min-width:700px) 700px, 100vw',
+          'sizes_image_styles' => array(
+            'large' => 'large',
+          ),
+        ),
       ),
       'test_breakpoint2' => array(
-        '1x' => 'test_style3',
+        '1x' => array(
+          'breakpoint_id' => 'test_breakpoint2',
+          'multiplier' => '1x',
+          'mapping_type' => 'image_style',
+          'image_style' => 'thumbnail',
+          'sizes' => '',
+          'sizes_image_styles' => array(),
+        ),
       )
     );
     $this->assertEquals($expected, $entity->getKeyedMappings());
 
     // Add another mapping to ensure keyed mapping static cache is rebuilt.
-    $entity->addMapping('test_breakpoint2', '2x', 'test_style4');
-    $expected['test_breakpoint2']['2x'] = 'test_style4';
+    $entity->addMapping('test_breakpoint2', '2x', array(
+      'mapping_type' => 'image_style',
+      'image_style' => 'medium',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    ));
+    $expected['test_breakpoint2']['2x'] = array(
+      'breakpoint_id' => 'test_breakpoint2',
+      'multiplier' => '2x',
+      'mapping_type' => 'image_style',
+      'image_style' => 'medium',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    );
     $this->assertEquals($expected, $entity->getKeyedMappings());
   }
 
@@ -174,25 +239,53 @@ public function testGetKeyedMappings() {
    */
   public function testGetMappings() {
     $entity = new ResponsiveImageMapping(array(''));
-    $entity->addMapping('test_breakpoint', '1x', 'test_style');
-    $entity->addMapping('test_breakpoint', '2x', 'test_style2');
-    $entity->addMapping('test_breakpoint2', '1x', 'test_style3');
+    $entity->addMapping('test_breakpoint', '1x', array(
+      'mapping_type' => 'image_style',
+      'image_style' => 'large',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    ));
+    $entity->addMapping('test_breakpoint', '2x', array(
+      'mapping_type' => 'sizes',
+      'image_style' => '',
+      'sizes' => '(min-width:700px) 700px, 100vw',
+      'sizes_image_styles' => array(
+        'large' => 'large',
+      ),
+    ));
+    $entity->addMapping('test_breakpoint2', '1x',  array(
+      'mapping_type' => 'image_style',
+      'image_style' => 'thumbnail',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    ));
 
     $expected = array(
       array(
         'breakpoint_id' => 'test_breakpoint',
         'multiplier' => '1x',
-        'image_style' => 'test_style',
+        'mapping_type' => 'image_style',
+        'image_style' => 'large',
+        'sizes' => '',
+        'sizes_image_styles' => array(),
       ),
       array(
         'breakpoint_id' => 'test_breakpoint',
         'multiplier' => '2x',
-        'image_style' => 'test_style2',
+        'mapping_type' => 'sizes',
+        'image_style' => '',
+        'sizes' => '(min-width:700px) 700px, 100vw',
+        'sizes_image_styles' => array(
+          'large' => 'large',
+        ),
       ),
       array(
         'breakpoint_id' => 'test_breakpoint2',
         'multiplier' => '1x',
-        'image_style' => 'test_style3',
+        'mapping_type' => 'image_style',
+        'image_style' => 'thumbnail',
+        'sizes' => '',
+        'sizes_image_styles' => array(),
       ),
     );
     $this->assertEquals($expected, $entity->getMappings());
@@ -204,9 +297,26 @@ public function testGetMappings() {
    */
   public function testRemoveMappings() {
     $entity = new ResponsiveImageMapping(array(''));
-    $entity->addMapping('test_breakpoint', '1x', 'test_style');
-    $entity->addMapping('test_breakpoint', '2x', 'test_style2');
-    $entity->addMapping('test_breakpoint2', '1x', 'test_style3');
+    $entity->addMapping('test_breakpoint', '1x', array(
+      'mapping_type' => 'image_style',
+      'image_style' => 'large',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    ));
+    $entity->addMapping('test_breakpoint', '2x', array(
+      'mapping_type' => 'sizes',
+      'image_style' => '',
+      'sizes' => '(min-width:700px) 700px, 100vw',
+      'sizes_image_styles' => array(
+        'large' => 'large',
+      ),
+    ));
+    $entity->addMapping('test_breakpoint2', '1x',  array(
+      'mapping_type' => 'image_style',
+      'image_style' => 'thumbnail',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    ));
 
     $this->assertTrue($entity->hasMappings());
     $entity->removeMappings();
@@ -221,9 +331,26 @@ public function testRemoveMappings() {
    */
   public function testSetBreakpointGroup() {
     $entity = new ResponsiveImageMapping(array('breakpointGroup' => 'test_group'));
-    $entity->addMapping('test_breakpoint', '1x', 'test_style');
-    $entity->addMapping('test_breakpoint', '2x', 'test_style2');
-    $entity->addMapping('test_breakpoint2', '1x', 'test_style3');
+    $entity->addMapping('test_breakpoint', '1x', array(
+      'mapping_type' => 'image_style',
+      'image_style' => 'large',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    ));
+    $entity->addMapping('test_breakpoint', '2x', array(
+      'mapping_type' => 'sizes',
+      'image_style' => '',
+      'sizes' => '(min-width:700px) 700px, 100vw',
+      'sizes_image_styles' => array(
+        'large' => 'large',
+      ),
+    ));
+    $entity->addMapping('test_breakpoint2', '1x',  array(
+      'mapping_type' => 'image_style',
+      'image_style' => 'thumbnail',
+      'sizes' => '',
+      'sizes_image_styles' => array(),
+    ));
 
     // Ensure that setting to same group does not remove mappings.
     $entity->setBreakpointGroup('test_group');