[DependencyInjection] Add ParameterBag::remove

src/Symfony/Component/DependencyInjection/ParameterBag/ParameterBag.php

@@ -126,6 +126,18 @@ class ParameterBag implements ParameterBagInterface
         return array_key_exists(strtolower($name), $this->parameters);
     }
 
+    /**
+     * Removes a parameter.
+     *
+     * @param string $key The key
+     *
+     * @api
+     */
+    public function remove($key)
+    {
+        unset($this->parameters[$key]);
+    }
+
     /**
      * Replaces parameter placeholders (%name%) by their values for all parameters.
      */

src/Symfony/Component/DependencyInjection/Tests/ParameterBag/ParameterBagTest.php

@@ -43,6 +43,19 @@ class ParameterBagTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(array(), $bag->all(), '->clear() removes all parameters');
     }
 
+    /**
+     * @covers Symfony\Component\DependencyInjection\ParameterBag\ParameterBag::remove
+     */
+    public function testRemove()
+    {
+        $bag = new ParameterBag(array(
+            'foo' => 'foo',
+            'bar' => 'bar',
+        ));
+        $bag->remove('foo');
+        $this->assertEquals(array('bar' => 'bar'), $bag->all(), '->remove() removes a parameter');
+    }
+
     /**
      * @covers Symfony\Component\DependencyInjection\ParameterBag\ParameterBag::get
      * @covers Symfony\Component\DependencyInjection\ParameterBag\ParameterBag::set