src: add c++ test coverage

[bnoordhuis]

Meta-issue for something that was discussed in today's TC meeting: test coverage for C++ code that is only tested indirectly now.

Strawman proposal: bundle gtest, make it part of make test and start churning out src/*_unittest.cc tests like chromium has.

Problem: most of the code in src/ is not very modular right now. Turning it into something that is easily testable will no doubt create a lot of churn. Probably unavoidable but it's acceptable to me.

/cc @indutny @piscisaureus @trevnorris - if we can get some consensus on this, I volunteer to do the initial work.

[indutny]

It is very interesting thing. What I am mostly curious about is - how much of the stuff will we be able to test within the C++? It seems to me that many if not most of the code is tightly bound to the JS.

The second question is even more interesting :) Do we want it to be cross-platform? Or can we do some raw socket() machinery in it? Like working with fds, and stuff like that.

[indutny]

+1 for this in general, though

[bnoordhuis]

It is very interesting thing. What I am mostly curious about is - how much of the stuff will we be able to test within the C++? It seems to me that many if not most of the code is tightly bound to the JS.

That's why I predict there will be a fair bit of churn, to break out the meat from the glue code. I think it's alright when tests set up a VM where it makes sense.

The second question is even more interesting :) Do we want it to be cross-platform? Or can we do some raw socket() machinery in it? Like working with fds, and stuff like that.

It should be cross-platform, with the platform-dependent bits guarded by #ifdef statements. Just like libuv, really. :-)

[indutny]

Sounds awesome! Go ahead with it :)

[jbergstroem]

Good idea indeed. Is there perhaps a .gyp for gtest somewhere? I'd really despise having to pull cmake or auto* into the dependency chain. Another plan could be making running these tests optional and assume you can handle installing gtest yourself?

[bnoordhuis]

I don't think there is one currently but it should be pretty easy to get it gypified. gtest core is only a handful of files.

[trevnorris]

I'm fine with this. Will it mean make test-addon will be removed/unneeded?

[bnoordhuis]

Not right away but it could, longer term. Not the part of make test-addon that scrapes the API documentation, though.