JsonApi doesn't break on no body fixtures in tests

[imsickofmaps]

But it does in production as JSON.parse("") throws errors.

[hodgestar]

@imsickofmaps Could you provide a link to the fixtures that worked?

I think what is happening here is that the HttpFixture class is looking at the Content-Type and seeing that the response is expected to be JSON and so encoding the response for you. I suspect the fixture had something like response: '' and Content-Type: application/json and so the fixture happily encodes the response to '""' for you. This is by design (since otherwise fixtures are a mess of double-encoded JSON) but perhaps there is a way we can make the design better for these cases.