public function testCredential()
{
$credential = new Credential("accessKeyId", "accessSecret");
$this->assertEquals("accessKeyId", $credential->getAccessKeyId());
$this->assertEquals("accessSecret", $credential->getAccessSecret());
$this->assertNotNull($credential->getRefreshDate());
$dateNow = gmdate('Y-m-d\\TH:i:s\\Z');
$credential->setExpiredDate(1);
$this->assertNotNull($credential->getExpiredDate());
$this->assertTrue($credential->getExpiredDate() > $dateNow);
}