This commit adds a testing framework modeled after the godoc tests. It builds
webhook in a temporary directory, runs it with the supplied `hooks_test.json`
configuration, and then tests different payloads. I use `/bin/echo` for the
test executable, so I've added build tags to exclude Windows.
Three minor (I hope) changes in functionality:
- I ended up moving everything from `init()` to `main()` because `init()` was
firing while trying to build the tests, and it was dying since `hooks.json`
didn't exist. I'm still not 100% sure `init()` was firing, but I didn't see
any real need for anything to be in `init()` in the first place.
- make sure logger is using `os.Stderr`
- don't send `http.StatusBadRequest` when the Hook rules don't match. "Bad
Request" is used to identify malformed requests. The request was properly
formed and processed, so I think we should send back `http.StatusOK`. For
example, if I setup a webhook rule to only execute when commits are made to
the `master` branch, we shouldn't send back `http.StatusBadRequest` when we
ingest a payload for the `development` branch.
The test payloads are pretty verbose and could probably be shortened, but I kind
of like having an example payload for each service. We can pare them down if we
want to do more focused, minimalist testing.
