public function testSort()
{
$params1 = ['aaa' => '111', 'bbb' => '2222', 'ccc' => '3333'];
$params2 = ['bbb' => '2222', 'ccc' => '3333', 'aaa' => '111'];
$signer = new Signer($params1);
$sign1 = $signer->signWithMD5($this->key);
$signer = new Signer($params2);
$sign2 = $signer->signWithMD5($this->key);
$this->assertEquals($sign1, $sign2);
}