Guzzle 6.3.0 response body wasn't returning the stream in a way which could be passed directly out as slim's response (content was blank), though it worked on earlier versions of Guzzle.
Fixed by fetching content and creating a new response body stream.
Coverage decreased (-0.05%) to 31.934% when pulling 4c9cbd16a035b6f6e34d10e93a6ee54d1cb785c5 on develop into 00b67b0294bb859e16bf2b633cd09dcefb7319e3 on master.
Guzzle 6.3.0 response body wasn't returning the stream in a way which could be passed directly out as slim's response (content was blank), though it worked on earlier versions of Guzzle. Fixed by fetching content and creating a new response body stream.
Also fixed mock email sending for testing.