Well, http://xkcd.com/927/ holds true again. I think these things are awesome -- though, I wish they weren't presented as something that is supposed to /reduce/ fragmentation. Perhaps it will at some point, but it probably won't -- just like the others.

I think the "C++ is different in different environments, making it hard to write portable C++ code" argument is pretty weak. Is C++ annoying across different environments? Hell yeah, but I fail to see how is this any different/worse than production code.

Test frameworks use some pretty crazy tricks to produce a pleasant syntax with good error debugging messages. For an example, see CATCH: https://github.com/philsquared/Catch/wiki

I'd imagine this sort of stuff is much harder to port across systems than regular production code.

Go doesn't have this problem because the Go Team doesn't believe that testing frameworks are a valid concept. For and If and Errorf are good enough for anyone.