Support using JSONRenderer in TEST_REQUEST_RENDERER_CLASSES

[stianpr]

It would be very nice to use the JSONRenderer as default request renderer in tests. In latest release it will break because it does not have any renderer context. So by supporting this a test could look something like this:

client = APIClient()
response = client.patch(
   '/api/companies/1'
    {'name': 'A new company name'},
    format='vnd.api+json'
)
assert response.status_code == status.HTTP_200_OK

Then we don't have to build the payload for data in correct JSON API spec 1.0. The renderer does that for us.

[jerel]

@stianpr this would be a nice enhancement. I don't have time to implement it myself at the moment but would certainly welcome a PR.

[sliverc]

This has been address with #396 hence closing this issue.