public function test_array_pull()
{
$array = array('id' => 1000, 'username' => 'allen', 'password' => '123456', 'email' => '*****@*****.**', 'created_at' => 1461317101);
$this->assertEquals(array('realname' => null), util::array_pull($array, 'realname'));
$this->assertEquals(array('username' => 'allen'), util::array_pull($array, 'username'));
$this->assertEquals(array('id' => 1000, 'username' => 'allen'), util::array_pull($array, array('id', 'username')));
$this->assertEquals(array(1000, 'allen'), util::array_pull($array, array('id', 'username'), false));
}