public function testExpressPurchaseFailure()
{
$httpResponse = $this->getMockHttpResponse('ExpressPurchaseFailure.txt');
$response = new ExpressAuthorizeResponse($this->getMockRequest(), $httpResponse->getBody());
$this->assertFalse($response->isSuccessful());
$this->assertNull($response->getExpressRedirectToken());
$this->assertNull($response->getTransactionReference());
$this->assertSame('This transaction cannot be processed. The amount to be charged is zero.', $response->getMessage());
}