This pull request contains 2 fixes: the first commit disallows NULL to be passed as a callback to prepare/idle/check handles and modifies the tests accordingly.
After the first commit, the build fails on unix (test-ref) because the event loop will run once even if all handles are unref'd. This wasn's apparent because the tests in test-ref used NULL as a callback. The second commit fixes this.
/cc @bnoordhuis @piscisaureus
prepare/idle/check: don't allow NULL callback
unix: fixed running loop when all handles are unref'd
Thanks for the lighning fast review @bnoordhuis ;-) I just force pushed with the suggested changes.
Thanks Saúl, landed in 33d5c49 and 4650a59.