[DependencyInjection] Fix Container::camelize to convert beginning and ending chars

To convert a service ID exactly like Container::get

src/Symfony/Component/DependencyInjection/Container.php

@@ -471,7 +471,7 @@ class Container implements IntrospectableContainerInterface
      */
     public static function camelize($id)
     {
-        return preg_replace_callback('/(^|_|\.)+(.)/', function ($match) { return ('.' === $match[1] ? '_' : '').strtoupper($match[2]); }, $id);
+        return strtr(ucwords(strtr($id, array('_' => ' ', '.' => '_ '))), array(' ' => ''));
     }
 
     /**

src/Symfony/Component/DependencyInjection/Tests/ContainerTest.php

@@ -30,6 +30,29 @@ class ContainerTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(array('foo' => 'bar'), $sc->getParameterBag()->all(), '__construct() takes an array of parameters as its first argument');
     }
 
+    /**
+     * @dataProvider dataForTestCamelize
+     */
+    public function testCamelize($id, $expected)
+    {
+        $this->assertEquals($expected, Container::camelize($id), sprintf('Container::camelize("%s")', $id));
+    }
+
+    public function dataForTestCamelize()
+    {
+        return array(
+            array('foo_bar', 'FooBar'),
+            array('foo.bar', 'Foo_Bar'),
+            array('foo.bar_baz', 'Foo_BarBaz'),
+            array('foo._bar', 'Foo_Bar'),
+            array('foo_.bar', 'Foo_Bar'),
+            array('_foo', 'Foo'),
+            array('.foo', '_Foo'),
+            array('foo_', 'Foo'),
+            array('foo.', 'Foo_'),
+        );
+    }
+
     /**
      * @covers Symfony\Component\DependencyInjection\Container::compile
      */