diff -u b/core/modules/breakpoint/breakpoint.module b/core/modules/breakpoint/breakpoint.module
--- b/core/modules/breakpoint/breakpoint.module
+++ b/core/modules/breakpoint/breakpoint.module
@@ -35,6 +35,8 @@
  * Implements hook_enable().
  *
  * Import breakpoints from all enabled themes.
+ *
+ * @todo: This should be removed if https://drupal.org/node/1813100 is resolved.
  */
 function breakpoint_enable() {
   // Import breakpoints from themes.
@@ -53,6 +55,8 @@
  *   An array of theme names.
  *
  * @see _breakpoint_theme_enabled()
+ *
+ * @todo: This should be removed if https://drupal.org/node/1813100 is resolved.
  */
 function breakpoint_themes_enabled($theme_list) {
   _breakpoint_theme_enabled($theme_list);
@@ -65,6 +69,8 @@
  *   An array of theme names.
  *
  * @see _breakpoint_delete_breakpoints()
+ *
+ * @todo: This should be removed if https://drupal.org/node/1813100 is resolved.
  */
 function breakpoint_themes_disabled($theme_list) {
   _breakpoint_delete_breakpoints($theme_list, Breakpoint::SOURCE_TYPE_THEME);
@@ -77,7 +83,9 @@
  *   An array of the modules that were enabled.
  *
  * @see _breakpoint_modules_enabled()
- */
+ *
+ * @todo: This should be removed if https://drupal.org/node/1813100 is resolved.
+*/
 function breakpoint_modules_enabled($modules) {
   _breakpoint_modules_enabled($modules);
 }
@@ -89,6 +97,8 @@
  *   An array of the modules that were uninstalled.
  *
  * @see _breakpoint_delete_breakpoints()
+ *
+ * @todo: This should be removed if https://drupal.org/node/1813100 is resolved.
  */
 function breakpoint_modules_uninstalled($modules) {
   _breakpoint_delete_breakpoints($modules, Breakpoint::SOURCE_TYPE_MODULE);
@@ -366,7 +376,7 @@
  * @return array
  *   An array containing breakpoint group labels indexed by their ids.
  */
-function breakpoint_group_labels() {
+function breakpoint_group_select_options() {
   $options = array();
   $breakpoint_groups = entity_load_multiple('breakpoint_group');
   foreach ($breakpoint_groups as $breakpoint_group) {
@@ -382,13 +392,13 @@
  * @return array
  *   An array containing breakpoints indexed by their ids.
  */
-function breakpoint_labels() {
+function breakpoint_select_options() {
   $options = array();
   $breakpoints = entity_load_multiple('breakpoint');
   foreach ($breakpoints as $breakpoint) {
     $options[$breakpoint->id()] = $breakpoint->label() . ' (' . $breakpoint->source . ' - ' . $breakpoint->sourceType .   ') [' . $breakpoint->mediaQuery . ']';
   }
-
+  asort($options);
   return $options;
 }
 
@@ -405,6 +415,9 @@
  *   Either Breakpoint::SOURCE_TYPE_THEME or Breakpoint::SOURCE_TYPE_MODULE.
  *
  * @return Drupal\breakpoint\BreakpointGroup
+ *
+ * @see _breakpoint_import_media_queries()
+ * @see _breakpoint_import_breakpoint_groups()
  */
 function _breakpoint_group_create_or_load($name, $label, $source, $source_type) {
   // Try loading the breakpoint group.
diff -u b/core/modules/breakpoint/lib/Drupal/breakpoint/Breakpoint.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Breakpoint.php
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/Breakpoint.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Breakpoint.php
@@ -32,7 +32,7 @@
   /**
    * Denotes that a breakpoint or breakpoint group is defined by the user.
    */
-  const SOURCE_TYPE_CUSTOM = 'custom';
+  const SOURCE_TYPE_USER_DEFINED = 'custom';
 
   /**
    * The breakpoint ID (config name).
@@ -83,9 +83,9 @@
    *   Allowed values:
    *     Breakpoint::SOURCE_TYPE_THEME
    *     Breakpoint::SOURCE_TYPE_MODULE
-   *     Breakpoint::SOURCE_TYPE_CUSTOM
+   *     Breakpoint::SOURCE_TYPE_USER_DEFINED
    */
-  public $sourceType = Breakpoint::SOURCE_TYPE_CUSTOM;
+  public $sourceType = Breakpoint::SOURCE_TYPE_USER_DEFINED;
 
   /**
    * The breakpoint weight.
@@ -134,19 +134,6 @@
   }
 
   /**
-   * Duplicates a breakpoint.
-   *
-   * The new breakpoint inherits the media query.
-   *
-   * @return Drupal\breakpoint\Breakpoint
-   */
-  public function duplicate() {
-    return entity_create('breakpoint', array(
-      'mediaQuery' => $this->mediaQuery,
-    ));
-  }
-
-  /**
    * Checks if the breakpoint is valid.
    *
    * @throws Drupal\breakpoint\InvalidBreakpointSourceTypeException
@@ -159,7 +146,7 @@
   public function isValid() {
     // Check for illegal values in breakpoint source type.
     if (!in_array($this->sourceType, array(
-        Breakpoint::SOURCE_TYPE_CUSTOM,
+        Breakpoint::SOURCE_TYPE_USER_DEFINED,
         Breakpoint::SOURCE_TYPE_MODULE,
         Breakpoint::SOURCE_TYPE_THEME)
       )) {
@@ -191,6 +178,8 @@
    * @see https://github.com/adobe/webkit/blob/master/Source/WebCore/css/
    */
   public static function isValidMediaQuery($media_query) {
+    // Array describing all known media features and the expected value type or
+    // an array containing the allowed values.
     $media_features = array(
       'width' => 'length', 'min-width' => 'length', 'max-width' => 'length',
       'height' => 'length', 'min-height' => 'length', 'max-height' => 'length',
@@ -213,7 +202,7 @@
       // Remove comments /* ... */.
       $media_query = preg_replace('/\/\*[\s\S]*?\*\//', '', $media_query);
 
-      // Check mediaQuery_list: S* [mediaQuery [ ',' S* mediaQuery ]* ]?
+      // Check media list.
       $parts = explode(',', $media_query);
       foreach ($parts as $part) {
         // Split on ' and '
@@ -221,15 +210,15 @@
         $media_type_found = FALSE;
         foreach ($query_parts as $query_part) {
           $matches = array();
-          // Check expression: '(' S* media_feature S* [ ':' S* expr ]? ')' S*
+          // Try to match: '(media_feature: value)' and variants.
           if (preg_match('/^\(([\w\-]+)(:\s?([\w\-\.]+))?\)/', trim($query_part), $matches)) {
-            // Single expression.
+            // Single expression like '(color)'.
             if (isset($matches[1]) && !isset($matches[2])) {
               if (!array_key_exists($matches[1], $media_features)) {
                 throw new InvalidBreakpointMediaQueryException('Invalid media feature detected.');
               }
             }
-            // Full expression.
+            // Full expression like '(min-width: 20em)'.
             elseif (isset($matches[3]) && !isset($matches[4])) {
               $value = trim($matches[3]);
               if (!array_key_exists($matches[1], $media_features)) {
@@ -249,6 +238,7 @@
                 switch ($media_features[$matches[1]]) {
                   case 'length':
                     $length_matches = array();
+                    // Check for a valid number and an allowed unit.
                     if (preg_match('/^(\-)?(\d+(?:\.\d+)?)?((?:|em|ex|px|cm|mm|in|pt|pc|deg|rad|grad|ms|s|hz|khz|dpi|dpcm))$/i', trim($value), $length_matches)) {
                       // Only -0 is allowed.
                       if ($length_matches[1] === '-' && $length_matches[2] !== '0') {
@@ -268,14 +258,14 @@
             }
           }
 
-          // Check [ONLY | NOT]? S* media_type
+          // Check for screen, only screen, not screen and variants.
           elseif (preg_match('/^((?:only|not)?\s?)([\w\-]+)$/i', trim($query_part), $matches)) {
             if ($media_type_found) {
               throw new InvalidBreakpointMediaQueryException('Only one media type is allowed.');
             }
             $media_type_found = TRUE;
           }
-          // Check illegal [ONLY | NOT]? S* media_type
+          // Check for (scan), (only scan), (not scan) and variants.
           elseif (preg_match('/^((?:only|not)\s?)\(([\w\-]+)\)$/i', trim($query_part), $matches)) {
             throw new InvalidBreakpointMediaQueryException('Invalid media query detected.');
           }
diff -u b/core/modules/breakpoint/lib/Drupal/breakpoint/BreakpointGroup.php b/core/modules/breakpoint/lib/Drupal/breakpoint/BreakpointGroup.php
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/BreakpointGroup.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/BreakpointGroup.php
@@ -69,11 +69,11 @@
    *   Allowed values:
    *     Breakpoint::SOURCE_TYPE_THEME
    *     Breakpoint::SOURCE_TYPE_MODULE
-   *     Breakpoint::SOURCE_TYPE_CUSTOM
+   *     Breakpoint::SOURCE_TYPE_USER_DEFINED
    *
    * @see Drupal\breakpoint\Breakpoint
    */
-  public $sourceType = Breakpoint::SOURCE_TYPE_CUSTOM;
+  public $sourceType = Breakpoint::SOURCE_TYPE_USER_DEFINED;
 
   /**
    * Overrides Drupal\config\ConfigEntityBase::__construct().
@@ -112,7 +112,7 @@
   public function isValid() {
     // Check for illegal values in breakpoint group source type.
     if (!in_array($this->sourceType, array(
-        Breakpoint::SOURCE_TYPE_CUSTOM,
+        Breakpoint::SOURCE_TYPE_USER_DEFINED,
         Breakpoint::SOURCE_TYPE_MODULE,
         Breakpoint::SOURCE_TYPE_THEME)
       )) {
@@ -132,20 +132,6 @@
   }
 
   /**
-   * Duplicates a breakpoint group.
-   *
-   * The new breakpoint group inherits the breakpoints.
-   *
-   * @return Drupal\breakpoint\BreakpointGroup
-   */
-  public function duplicate() {
-    return entity_create('breakpoint_group', array(
-      'breakpoints' => array_keys($this->breakpoints),
-      'name' => 'clone_of_' . $this->name,
-    ));
-  }
-
-  /**
    * Adds a breakpoint using a name and a media query.
    *
    * @param string $name
@@ -176,7 +162,7 @@
    *
    * The breakpoint name is either the machine_name or the id of a breakpoint.
    *
-   * @param type $breakpoints
+   * @param array $breakpoints
    *   Array containing breakpoints keyed by their id.
    */
   public function addBreakpoints($breakpoints) {
diff -u b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointAPITest.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointAPITest.php
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointAPITest.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointAPITest.php
@@ -17,9 +17,6 @@
  */
 class BreakpointAPITest extends BreakpointTestBase {
 
-  /**
-   * Drupal\simpletest\WebTestBase\getInfo().
-   */
   public static function getInfo() {
     return array(
       'name' => 'Breakpoint general API functions',
@@ -46,11 +43,11 @@
     catch (InvalidBreakpointSourceTypeException $e) {
       $exception = TRUE;
     }
-    $this->assertTrue($exception, t('breakpoint_config_name: An exception is thrown when an invalid sourceType is entered.'));
+    $this->assertTrue($exception, 'breakpoint_config_name: An exception is thrown when an invalid sourceType is entered.');
 
     // Try an invalid source.
     $breakpoint->id = '';
-    $breakpoint->sourceType = Breakpoint::SOURCE_TYPE_CUSTOM;
+    $breakpoint->sourceType = Breakpoint::SOURCE_TYPE_USER_DEFINED;
     $breakpoint->source = 'custom*_module source';
 
     $exception = FALSE;
@@ -60,7 +57,7 @@
     catch (InvalidBreakpointSourceException $e) {
       $exception = TRUE;
     }
-    $this->assertTrue($exception, t('breakpoint_config_name: An exception is thrown when an invalid source is entered.'));
+    $this->assertTrue($exception, 'breakpoint_config_name: An exception is thrown when an invalid source is entered.');
 
     // Try an invalid name (make sure there is at least once capital letter).
     $breakpoint->id = '';
@@ -74,7 +71,7 @@
     catch (InvalidBreakpointNameException $e) {
       $exception = TRUE;
     }
-    $this->assertTrue($exception, t('breakpoint_config_name: An exception is thrown when an invalid name is entered.'));
+    $this->assertTrue($exception, 'breakpoint_config_name: An exception is thrown when an invalid name is entered.');
 
     // Try a valid breakpoint.
     $breakpoint->id = '';
@@ -89,6 +86,6 @@
       $exception = TRUE;
     }
-    $this->assertFalse($exception, t('breakpoint_config_name: No exception is thrown when a valid breakpoint is passed.'));
-    $this->assertEqual($breakpoint->id(), Breakpoint::SOURCE_TYPE_CUSTOM . '.custom_module.' . $breakpoint->name, t('breakpoint_config_name: A id is set when a valid breakpoint is passed.'));
+    $this->assertFalse($exception, 'breakpoint_config_name: No exception is thrown when a valid breakpoint is passed.');
+    $this->assertEqual($breakpoint->id(), Breakpoint::SOURCE_TYPE_USER_DEFINED . '.custom_module.' . $breakpoint->name, 'breakpoint_config_name: A id is set when a valid breakpoint is passed.');
   }
 }
reverted:
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointCrudTest.php
+++ /dev/null
@@ -1,57 +0,0 @@
-<?php
-/**
- * @file
- * Definition of Drupal\breakpoint\Tests\BreakpointCrudTest.
- */
-
-namespace Drupal\breakpoint\Tests;
-
-use Drupal\breakpoint\Tests\BreakpointTestBase;
-use Drupal\breakpoint\Breakpoint;
-
-/**
- * Tests for breakpoint CRUD operations.
- */
-class BreakpointCrudTest extends BreakpointTestBase {
-
-  /**
-   * Drupal\simpletest\WebTestBase\getInfo().
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'Breakpoint CRUD operations',
-      'description' => 'Test creation, loading, updating, deleting of breakpoints.',
-      'group' => 'Breakpoint',
-    );
-  }
-
-  /**
-   * Test CRUD operations for breakpoints.
-   */
-  public function testBreakpointCrud() {
-    // Add a breakpoint with minimum data only.
-    $breakpoint = entity_create('breakpoint', array(
-      'label' => drupal_strtolower($this->randomName()),
-      'mediaQuery' => '(min-width: 600px)',
-    ));
-    $breakpoint->save();
-
-    $this->verifyBreakpoint($breakpoint);
-
-    // Test breakpoint_load_all
-    $all_breakpoints = entity_load_multiple('breakpoint');
-    $config_name = $breakpoint->id();
-    $this->assertTrue(isset($all_breakpoints[$config_name]), t('breakpoint_load_all: New breakpoint is present when loading all breakpoints.'));
-    $this->verifyBreakpoint($breakpoint, $all_breakpoints[$config_name]);
-
-    // Update the breakpoint.
-    $breakpoint->weight = 1;
-    $breakpoint->multipliers['2x'] = '2x';
-    $breakpoint->save();
-    $this->verifyBreakpoint($breakpoint);
-
-    // Delete the breakpoint.
-    $breakpoint->delete();
-    $this->assertFalse(breakpoint_load($config_name), t('breakpoint_load: Loading a deleted breakpoint returns false.'), t('Breakpoints API'));
-  }
-}
diff -u b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupAPITest.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupAPITest.php
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupAPITest.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupAPITest.php
@@ -18,9 +18,6 @@
  */
 class BreakpointGroupAPITest extends BreakpointGroupTestBase {
 
-  /**
-   * Drupal\simpletest\WebTestBase\getInfo().
-   */
   public static function getInfo() {
     return array(
       'name' => 'Breakpoint group general API functions',
@@ -49,11 +46,11 @@
     catch (InvalidBreakpointSourceTypeException $e) {
       $exception = TRUE;
     }
-    $this->assertTrue($exception, t('An exception is thrown when an invalid sourceType is entered.'));
+    $this->assertTrue($exception, 'An exception is thrown when an invalid sourceType is entered.');
 
     // Try an invalid source.
     $breakpoint_group->name = '';
-    $breakpoint_group->sourceType = Breakpoint::SOURCE_TYPE_CUSTOM;
+    $breakpoint_group->sourceType = Breakpoint::SOURCE_TYPE_USER_DEFINED;
     $breakpoint_group->source = 'custom*_module source';
 
     $exception = FALSE;
@@ -63,7 +60,7 @@
     catch (InvalidBreakpointSourceException $e) {
       $exception = TRUE;
     }
-    $this->assertTrue($exception, t('An exception is thrown when an invalid source is entered.'));
+    $this->assertTrue($exception, 'An exception is thrown when an invalid source is entered.');
 
     // Try a valid breakpoint_group.
     $breakpoint_group->name = 'test';
@@ -77,5 +74,5 @@
       $exception = TRUE;
     }
-    $this->assertFalse($exception, t('No exception is thrown when a valid data is passed.'));
+    $this->assertFalse($exception, 'No exception is thrown when a valid data is passed.');
   }
 }
reverted:
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupCrudTest.php
+++ /dev/null
@@ -1,72 +0,0 @@
-<?php
-/**
- * @file
- * Definition of Drupal\breakpoint\Tests\BreakpointGroupCrudTest.
- */
-
-namespace Drupal\breakpoint\Tests;
-
-use Drupal\breakpoint\Tests\BreakpointGroupTestBase;
-use Drupal\breakpoint\BreakpointGroup;
-use Drupal\breakpoint\Breakpoint;
-
-/**
- * Tests for breakpoint group CRUD operations.
- */
-class BreakpointGroupCrudTest extends BreakpointGroupTestBase {
-
-  /**
-   * Drupal\simpletest\WebTestBase\getInfo().
-   */
-  public static function getInfo() {
-    return array(
-      'name' => 'Breakpoint group CRUD operations',
-      'description' => 'Test creation, loading, updating, deleting of breakpoint groups.',
-      'group' => 'Breakpoint',
-    );
-  }
-
-  /**
-   * Test CRUD operations for breakpoint groups.
-   */
-  public function testBreakpointGroupCrud() {
-    // Add breakpoints.
-    $breakpoints = array();
-    for ($i = 0; $i <= 3; $i++) {
-      $width = ($i + 1) * 200;
-      $breakpoint = entity_create('breakpoint', array(
-        'name' => drupal_strtolower($this->randomName()),
-        'weight' => $i,
-        'mediaQuery' => "(min-width: {$width}px)",
-      ));
-      $breakpoint->save();
-      $breakpoints[$breakpoint->id()] = $breakpoint;
-    }
-    // Add a breakpoint group with minimum data only.
-    $label = $this->randomName();
-
-    $group = entity_create('breakpoint_group', array(
-      'label' => $label,
-      'name' => drupal_strtolower($label),
-    ));
-    $group->save();
-    $this->verifyBreakpointGroup($group);
-
-    // Update the breakpoint group.
-    $group->breakpoints = array_keys($breakpoints);
-    $group->save();
-    $this->verifyBreakpointGroup($group);
-
-    // Duplicate the breakpoint group.
-    $new_set = entity_create('breakpoint_group', array(
-      'breakpoints' => $group->breakpoints,
-      'name' => 'clone_of_' . $group->name,
-    ));
-    $duplicated_set = $group->duplicate();
-    $this->verifyBreakpointGroup($duplicated_set, $new_set);
-
-    // Delete the breakpoint group.
-    $group->delete();
-    $this->assertFalse(entity_load('breakpoint_group', $group->id()), t('breakpoint_group_load: Loading a deleted breakpoint group returns false.'), t('Breakpoints API'));
-  }
-}
diff -u b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupTestBase.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupTestBase.php
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupTestBase.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupTestBase.php
@@ -21,9 +21,6 @@
    */
   public static $modules = array('breakpoint');
 
-  /**
-   * Drupal\simpletest\WebTestBase\setUp().
-   */
   public function setUp() {
     parent::setUp();
   }
@@ -39,7 +36,6 @@
       'breakpoints',
       'sourceType',
     );
-    $assert_set = t('Breakpoints API');
 
     // Verify breakpoint_group_load().
     $compare_set = is_null($compare_set) ? entity_load('breakpoint_group', $group->id()) : $compare_set;
@@ -50,7 +46,7 @@
         '%property' => $property,
       );
       if (is_array($compare_set->{$property})) {
-        $this->assertEqual(array_keys($compare_set->{$property}), array_keys($group->{$property}), t('breakpoint_group_load: Proper %property for breakpoint group %group.', $t_args), $assert_set);
+        $this->assertEqual(array_keys($compare_set->{$property}), array_keys($group->{$property}), format_string('breakpoint_group_load: Proper %property for breakpoint group %group.', $t_args), 'Breakpoint API');
       }
       else {
         $t_args = array(
@@ -59,7 +55,7 @@
           '%property1' => $compare_set->{$property},
           '%property2' => $group->{$property},
         );
-        $this->assertEqual($compare_set->{$property}, $group->{$property}, t('breakpoint_group_load: Proper %property: %property1 == %property2 for breakpoint group %group.', $t_args), $assert_set);
+        $this->assertEqual($compare_set->{$property}, $group->{$property}, format_string('breakpoint_group_load: Proper %property: %property1 == %property2 for breakpoint group %group.', $t_args), 'Breakpoint API');
       }
     }
   }
diff -u b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointMediaQueryTest.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointMediaQueryTest.php
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointMediaQueryTest.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointMediaQueryTest.php
@@ -15,9 +15,6 @@
  */
 class BreakpointMediaQueryTest extends UnitTestBase {
 
-  /**
-   * Drupal\simpletest\WebTestBase\getInfo().
-   */
   public static function getInfo() {
     return array(
       'name' => 'Breakpoint media query tests',
@@ -42,6 +39,7 @@
       '(min-width: 0px)',
       'all and (min-width: 480px) and (max-width: 959px)',
       'all and (min-width: 960px)',
+      // Other media queries.
       '(orientation)',
       'all and (orientation)',
       'not all and (orientation)',
@@ -118,7 +116,7 @@
         $this->assertFalse(Breakpoint::isValidMediaQuery($media_query), $media_query . ' is not valid.');
       }
       catch (InvalidBreakpointMediaQueryException $e) {
-        $this->assertTrue(TRUE, $media_query . ' is not valid.');
+        $this->assertTrue(TRUE, format_string('%media_query is not valid.', array('%media_query' => $media_query)));
       }
     }
   }
diff -u b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointTestBase.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointTestBase.php
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointTestBase.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointTestBase.php
@@ -21,9 +21,6 @@
    */
   public static $modules = array('breakpoint');
 
-  /**
-   * Drupal\simpletest\WebTestBase\setUp().
-   */
   public function setUp() {
     parent::setUp();
   }
@@ -40,7 +37,6 @@
       'weight',
       'multipliers',
     );
-    $assert_group = t('Breakpoints API');
 
     // Verify breakpoint_load().
     $compare_breakpoint = is_null($compare_breakpoint) ? breakpoint_load($breakpoint->id()) : $compare_breakpoint;
@@ -49,7 +45,7 @@
         '%breakpoint' => $breakpoint->label(),
         '%property' => $property,
       );
-      $this->assertEqual($compare_breakpoint->{$property}, $breakpoint->{$property}, t('breakpoint_load: Proper %property for breakpoint %breakpoint.', $t_args), $assert_group);
+      $this->assertEqual($compare_breakpoint->{$property}, $breakpoint->{$property}, format_string('breakpoint_load: Proper %property for breakpoint %breakpoint.', $t_args), 'Breakpoint API');
     }
   }
 }
diff -u b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointThemeTest.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointThemeTest.php
--- b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointThemeTest.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointThemeTest.php
@@ -22,9 +22,6 @@
    */
   public static $modules = array('breakpoint_theme_test');
 
-  /**
-   * Drupal\simpletest\WebTestBase\getInfo().
-   */
   public static function getInfo() {
     return array(
       'name' => 'Breakpoint theme functionality',
@@ -33,9 +30,6 @@
     );
   }
 
-  /**
-   * Drupal\simpletest\WebTestBase\setUp().
-   */
   public function setUp() {
     parent::setUp();
     theme_enable(array('breakpoint_test_theme'));
@@ -65,7 +59,7 @@
 
     // Disable the test theme and verify the breakpoint group is deleted.
     theme_disable(array('breakpoint_test_theme'));
-    $this->assertFalse(entity_load('breakpoint_group', $breakpoint_group_obj->id()), t('breakpoint_group_load: Loading a deleted breakpoint group returns false.'), t('Breakpoints API'));
+    $this->assertFalse(entity_load('breakpoint_group', $breakpoint_group_obj->id()), 'breakpoint_group_load: Loading a deleted breakpoint group returns false.', 'Breakpoint API');
   }
 
   /**
@@ -74,7 +68,7 @@
   public function testThemeBreakpointGroup() {
     // Verify the breakpoint group 'test' was created by breakpoint_test_theme.
     $breakpoint_group_obj = entity_create('breakpoint_group', array(
-      'label' => 'Test',
+      'label' => 'Test Theme',
       'name' => 'test',
       'sourceType' => Breakpoint::SOURCE_TYPE_THEME,
       'source' => 'breakpoint_test_theme',
@@ -91,7 +85,7 @@
 
     // Disable the test theme and verify the breakpoint group is deleted.
     theme_disable(array('breakpoint_test_theme'));
-    $this->assertFalse(entity_load('breakpoint_group', $breakpoint_group_obj->id()), t('breakpoint_group_load: Loading a deleted breakpoint group returns false.'), t('Breakpoints API'));
+    $this->assertFalse(entity_load('breakpoint_group', $breakpoint_group_obj->id()), 'breakpoint_group_load: Loading a deleted breakpoint group returns false.', 'Breakpoint API');
   }
 
   /**
diff -u b/core/modules/breakpoint/tests/themes/breakpoint_test_theme/config/breakpoint_test_theme.breakpoint_groups.yml b/core/modules/breakpoint/tests/themes/breakpoint_test_theme/config/breakpoint_test_theme.breakpoint_groups.yml
--- b/core/modules/breakpoint/tests/themes/breakpoint_test_theme/config/breakpoint_test_theme.breakpoint_groups.yml
+++ b/core/modules/breakpoint/tests/themes/breakpoint_test_theme/config/breakpoint_test_theme.breakpoint_groups.yml
@@ -1,5 +1,5 @@
 test:
-  label: Test
+  label: Test Theme
   breakpoints:
     - mobile
     - narrow
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointCRUDTest.php
@@ -0,0 +1,54 @@
+<?php
+/**
+ * @file
+ * Definition of Drupal\breakpoint\Tests\BreakpointCRUDTest.
+ */
+
+namespace Drupal\breakpoint\Tests;
+
+use Drupal\breakpoint\Tests\BreakpointTestBase;
+use Drupal\breakpoint\Breakpoint;
+
+/**
+ * Tests for breakpoint CRUD operations.
+ */
+class BreakpointCRUDTest extends BreakpointTestBase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Breakpoint CRUD operations',
+      'description' => 'Test creation, loading, updating, deleting of breakpoints.',
+      'group' => 'Breakpoint',
+    );
+  }
+
+  /**
+   * Test CRUD operations for breakpoints.
+   */
+  public function testBreakpointCRUD() {
+    // Add a breakpoint with minimum data only.
+    $breakpoint = entity_create('breakpoint', array(
+      'label' => drupal_strtolower($this->randomName()),
+      'mediaQuery' => '(min-width: 600px)',
+    ));
+    $breakpoint->save();
+
+    $this->verifyBreakpoint($breakpoint);
+
+    // Test breakpoint_load_all
+    $all_breakpoints = entity_load_multiple('breakpoint');
+    $config_name = $breakpoint->id();
+    $this->assertTrue(isset($all_breakpoints[$config_name]), 'breakpoint_load_all: New breakpoint is present when loading all breakpoints.');
+    $this->verifyBreakpoint($breakpoint, $all_breakpoints[$config_name]);
+
+    // Update the breakpoint.
+    $breakpoint->weight = 1;
+    $breakpoint->multipliers['2x'] = '2x';
+    $breakpoint->save();
+    $this->verifyBreakpoint($breakpoint);
+
+    // Delete the breakpoint.
+    $breakpoint->delete();
+    $this->assertFalse(breakpoint_load($config_name), 'breakpoint_load: Loading a deleted breakpoint returns false.', 'Breakpoints API');
+  }
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupCRUDTest.php
@@ -0,0 +1,61 @@
+<?php
+/**
+ * @file
+ * Definition of Drupal\breakpoint\Tests\BreakpointGroupCRUDTest.
+ */
+
+namespace Drupal\breakpoint\Tests;
+
+use Drupal\breakpoint\Tests\BreakpointGroupTestBase;
+use Drupal\breakpoint\BreakpointGroup;
+use Drupal\breakpoint\Breakpoint;
+
+/**
+ * Tests for breakpoint group CRUD operations.
+ */
+class BreakpointGroupCRUDTest extends BreakpointGroupTestBase {
+
+  public static function getInfo() {
+    return array(
+      'name' => 'Breakpoint group CRUD operations',
+      'description' => 'Test creation, loading, updating, deleting of breakpoint groups.',
+      'group' => 'Breakpoint',
+    );
+  }
+
+  /**
+   * Test CRUD operations for breakpoint groups.
+   */
+  public function testBreakpointGroupCRUD() {
+    // Add breakpoints.
+    $breakpoints = array();
+    for ($i = 0; $i <= 3; $i++) {
+      $width = ($i + 1) * 200;
+      $breakpoint = entity_create('breakpoint', array(
+        'name' => drupal_strtolower($this->randomName()),
+        'weight' => $i,
+        'mediaQuery' => "(min-width: {$width}px)",
+      ));
+      $breakpoint->save();
+      $breakpoints[$breakpoint->id()] = $breakpoint;
+    }
+    // Add a breakpoint group with minimum data only.
+    $label = $this->randomName();
+
+    $group = entity_create('breakpoint_group', array(
+      'label' => $label,
+      'name' => drupal_strtolower($label),
+    ));
+    $group->save();
+    $this->verifyBreakpointGroup($group);
+
+    // Update the breakpoint group.
+    $group->breakpoints = array_keys($breakpoints);
+    $group->save();
+    $this->verifyBreakpointGroup($group);
+
+    // Delete the breakpoint group.
+    $group->delete();
+    $this->assertFalse(entity_load('breakpoint_group', $group->id()), 'breakpoint_group_load: Loading a deleted breakpoint group returns false.', 'Breakpoints API');
+  }
+}