public function testDeleteField()
{
$obj = new Object("TestObject");
$obj->delete("tags");
$this->assertNull($obj->get("tags"));
$obj->set("tags", array("frontend", "javascript"));
$this->assertEquals(array("frontend", "javascript"), $obj->get("tags"));
$obj->delete("tags");
$this->assertNull($obj->get("tags"));
$obj->addIn("tags", "frontend");
$this->assertEquals(array("frontend"), $obj->get("tags"));
}