public function testDefaultConfiguration()
 {
     $configuration = new Configuration(new TestCredentials());
     $this->assertInstanceOf('Team3\\PayU\\Configuration\\Credentials\\CredentialsInterface', $configuration->getCredentials());
     $this->assertEquals('https', $configuration->getProtocol());
     $this->assertEquals('secure.payu.com', $configuration->getDomain());
     $this->assertEquals('api', $configuration->getPath());
     $this->assertEquals('v2_1', $configuration->getVersion());
     $this->assertInstanceOf('Team3\\PayU\\Configuration\\Credentials\\TestCredentials', $configuration->getCredentials());
     $this->assertEquals('https://secure.payu.com/api/v2_1', $configuration->getAPIUrl());
 }