public function testSerialize()
{
$expected = ['locked' => 'false', 'username' => null, 'password' => null];
$actual = $this->lock->serialize();
$this->assertEquals($expected, $actual);
$lock = $this->_getLock(['locked' => true, 'username' => 'abc', 'password' => '123']);
$actual = $lock->serialize();
$expected = ['locked' => 'true', 'username' => 'abc', 'password' => '123'];
$this->assertEquals($expected, $actual);
}