Comment 2 for bug 597791

I agree, it is pretty complex! I wanted to add a test for https://bugs.edge.launchpad.net/bzr/+bug/656667 and while the parameterization is quite thorough it's not obvious where to put it.

My inclination would be to split by per_* but this case does perhaps show that naming things that way might get unwieldy if there are multiple variables.

Another approach would be to say, in each class

 variations = [ByHttpClientImplementation, ByHttpProtocolVersion]

and expand from that. It would get reduce the action-at-a-distance effect, and perhaps make later manipulations easier.