public function testAddChildAndGetChildren()
 {
     $child1 = $this->mockedNode(function ($element) {
         return $element['key1'];
     });
     $child2 = $this->mockedNode(function ($element) {
         return $element['key2'];
     });
     $this->treeBuilder->addChild($child1)->addChild($child2);
     $this->assertEquals(array($child1, $child2), $this->treeBuilder->getChildren());
 }