All CLA requirements met.

@ryu1kn While tests are great, I'm not too happy in having stubs in the git tests. Either make them not use stubs, or remove them.

Repository’s getCommit and deleteRef are not pure functions and behave differently depending on the outer world or make side effects; so to test them, i need to stub dependency or record the call from the repository. If you don’t want stub, i think i have to remove the tests i wrote...

@joaomoreno Can you think of better way of writing those tests? I believe those tests, especially the ones for Repository#getCommit are showing what you can expect from the method and so valuable. I wonder if we want to keep them.

Or I can test not the whole Repository#getCommit but only the logic of parsing git output by extracting it as an exported function. I usually don't export things from a module only for testing purpose, but looks like this is how we do it.

@joaomoreno I've updated the PR. How does it look now?

@joaomoreno Haven't had a chance to look at it again?

Thanks! 🍻