GuzzleHttp\Psr7\_parse_message isn't able to parse RestGenericSubscriptionSuccess.txt because the message has no content in RestGatewayTest (https://travis-ci.org/thephpleague/omnipay-paypal/jobs/489941682#L601). This PR adds content to the message so the tests no longer fail.
GuzzleHttp\Psr7\_parse_message
isn't able to parseRestGenericSubscriptionSuccess.txt
because the message has no content inRestGatewayTest
(https://travis-ci.org/thephpleague/omnipay-paypal/jobs/489941682#L601). This PR adds content to the message so the tests no longer fail.