commit 631e9c072dbd16030ea18c44ec5c23ad7fa17db0
Author: Joel Pittet <joel@pittet.ca>
Date:   Thu Jul 31 21:53:53 2014 -0700

    addClass/removeClass added and a few more tests, no more class.add and class.remove

diff --git a/core/lib/Drupal/Core/Template/Attribute.php b/core/lib/Drupal/Core/Template/Attribute.php
index ffef99a..6f5a779 100644
--- a/core/lib/Drupal/Core/Template/Attribute.php
+++ b/core/lib/Drupal/Core/Template/Attribute.php
@@ -117,23 +117,65 @@ public function offsetExists($name) {
   }
 
   /**
-   * Adds the argument values to the class element.
+   * Adds the argument values by merging them on to the value array.
+   *
+   * @return \Drupal\Core\Template\Attribute
+   *   The attribute with the class arguments added.
    */
   public function addClass() {
     $args = func_get_args();
+    $classes = array();
     foreach ($args as $arg) {
-      $this->storage['class']->add($arg);
+      // Merge the values passed in from the classes array.
+      // The argument is cast to an array to support comma separated single
+      // values or one or more array arguments.
+      $classes = array_merge($classes, (array) $arg);
+    }
+    // var_dump($classes);
+
+    // Merge if there are values, just add them otherwise.
+    if (isset($this->storage['class']) && $this->storage['class'] instanceOf AttributeArray && !empty($this->storage['class']->value())) {
+      // Merge the values passed in from the class value array.
+      $classes = array_merge($this->storage['class']->value(), $classes);
+      // Filter out any empty values.
+      $classes = array_filter($classes);
+      $this->storage['class']->exchangeArray($classes);
+    }
+    else {
+      // Filter out any empty values.
+      $classes = array_filter($classes);
+      $this->offsetSet('class', $classes);
     }
+
+    // var_dump($this->storage['class']);
+    return $this;
   }
 
   /**
-   * Removes the argument values from the class element.
+   * Removes the argument values from the value array.
+   *
+   * @return \Drupal\Core\Template\Attribute
+   *   The attribute with the class arguments removed.
    */
   public function removeClass() {
-    $args = func_get_args();
-    foreach ($args as $arg) {
-      $this->storage['class']->remove($arg);
+    // With no class attribute, there is no need to remove.
+    if (isset($this->storage['class']) && $this->storage['class'] instanceOf AttributeArray) {
+      $args = func_get_args();
+      $classes = array();
+      foreach ($args as $arg) {
+        // Merge the values passed in from the classes array.
+        // The argument is cast to an array to support comma separated single
+        // values or one or more array arguments.
+        $classes = array_merge($classes, (array) $arg);
+      }
+
+      // Remove the values passed in from the value array.
+      $classes = array_diff($this->storage['class']->value(), $classes);
+      // Filter out any empty values.
+      $classes = array_filter($classes);
+      $this->storage['class']->exchangeArray($classes);
     }
+    return $this;
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Template/AttributeArray.php b/core/lib/Drupal/Core/Template/AttributeArray.php
index 277a9bb..a204f4b 100644
--- a/core/lib/Drupal/Core/Template/AttributeArray.php
+++ b/core/lib/Drupal/Core/Template/AttributeArray.php
@@ -70,44 +70,6 @@ public function __toString() {
   }
 
   /**
-   * Adds the argument values by merging them on to the value array.
-   *
-   * @param mixed $value
-   *   A value, or array of values, to add to the array.
-   *
-   * @return \Drupal\Core\Template\AttributeArray
-   *   The attribute array with the arguments added.
-   */
-  public function add($value) {
-    // Merge the values passed in from the value array.
-    // The argument is cast to an array to support comma separated single
-    // values or one or more array arguments.
-    $this->value = array_merge($this->value, (array) $value);
-    // Filter out any empty values.
-    $this->value = array_filter($this->value);
-    return $this;
-  }
-
-  /**
-   * Removes the argument values from the value array.
-   *
-   * @param mixed $value
-   *   A value, or array of values, to remove from the array.
-   *
-   * @return \Drupal\Core\Template\AttributeArray
-   *   The attribute array with the arguments removed.
-   */
-  public function remove($value) {
-    // Remove the values passed in from the value array.
-    // The argument is cast to an array to support comma separated single
-    // values or one or more array arguments.
-    $this->value = array_diff($this->value, (array) $value);
-    // Filter out any empty values.
-    $this->value = array_filter($this->value);
-    return $this;
-  }
-
-  /**
    * Implements IteratorAggregate::getIterator().
    */
   public function getIterator() {
@@ -121,4 +83,21 @@ public function value() {
     return $this->value;
   }
 
+  /**
+   * Exchange the array for another one.
+   *
+   * @see ArrayObject::exchangeArray
+   *
+   * @param  array $input
+   *   The array input to replace the internal value.
+   *
+   * @return array
+   *   The old array value.
+   */
+  public function exchangeArray($input) {
+    $old = $this->value;
+    $this->value = $input;
+    return $old;
+  }
+
 }
diff --git a/core/tests/Drupal/Tests/Core/Template/AttributeTest.php b/core/tests/Drupal/Tests/Core/Template/AttributeTest.php
index b8fc41d..b73321e 100644
--- a/core/tests/Drupal/Tests/Core/Template/AttributeTest.php
+++ b/core/tests/Drupal/Tests/Core/Template/AttributeTest.php
@@ -57,23 +57,30 @@ public function testRemove() {
     $this->assertFalse(isset($attribute['class']));
   }
 
-
   /**
    * Tests adding class attributes with the AttributeArray helper method.
+   * @covers ::addClass()
    */
   public function testAddClasses() {
-    $attribute = new Attribute(array('class' => array('example-class')));
+
+    // Add empty Attribute object with no classes.
+    $attribute = new Attribute();
+    // Add one class.
+    $attribute->addClass('banana');
+
+    var_dump($attribute);
+    $this->assertEquals(new AttributeArray('class', array('banana')), $attribute['class']);
 
     // Add one class.
     $attribute->addClass('aa');
-    $this->assertEquals(new AttributeArray('class', array('example-class', 'aa')), $attribute['class']);
+    $this->assertEquals(new AttributeArray('class', array('banana', 'aa')), $attribute['class']);
 
     // Add multiple classes.
     $attribute->addClass('xx', 'yy');
     $this->assertEquals(
       new AttributeArray(
         'class',
-        array('example-class', 'aa', 'xx', 'yy')),
+        array('banana', 'aa', 'xx', 'yy')),
       $attribute['class']
     );
 
@@ -82,22 +89,19 @@ public function testAddClasses() {
     $this->assertEquals(
       new AttributeArray(
         'class',
-        array('example-class', 'aa', 'xx', 'yy', 'red', 'green', 'blue')
+        array('banana', 'aa', 'xx', 'yy', 'red', 'green', 'blue')
       ),
       $attribute['class']
     );
-
   }
 
   /**
    * Tests removing class attributes with the AttributeArray helper method.
+   * @covers ::removeClass()
    */
   public function testRemoveClasses() {
-    $attribute = new Attribute(
-      array(
-        'class' => array('example-class', 'aa', 'xx', 'yy', 'red', 'green', 'blue'),
-      )
-    );
+    $classes = array('example-class', 'aa', 'xx', 'yy', 'red', 'green', 'blue');
+    $attribute = new Attribute(array('class' => $classes));
 
     // Remove one class.
     $attribute->removeClass('example-class');
@@ -114,13 +118,20 @@ public function testRemoveClasses() {
 
   /**
    * Tests removing class attributes with the AttributeArray helper method.
+   * @covers ::removeClass()
+   * @covers ::addClass()
    */
   public function testChainAddRemoveClasses() {
     $attribute = new Attribute(
       array('class' => array('example-class', 'red', 'green', 'blue'))
     );
-    unset($attribute['class']);
-    $this->assertFalse(isset($attribute['class']));
+
+    $attribute
+      ->removeClass(array('red', 'green', 'pink'))
+      ->addClass(array('apple', 'lime', 'grapefruit'))
+      ->addClass(array('banana'));
+    $expected = array('example-class', 'blue', 'apple', 'lime', 'grapefruit', 'banana');
+    $this->assertArrayEquals($expected, $attribute['class']->value(), 'Attributes chained');
   }
 
   /**