public function testChildren()
 {
     $child = $this->getMock('JLM\\ProductBundle\\Model\\ProductCategoryInterface');
     $this->assertCount(0, $this->entity->getChildren());
     $this->assertTrue($this->entity->addChild($child));
     $this->assertCount(1, $this->entity->getChildren());
     $this->assertTrue($this->entity->removeChild($child));
     $this->assertCount(0, $this->entity->getChildren());
 }