add extra tests

[pjfanning]

based on comments in #26

fyi @vy

[vy]

@pjfanning, thanks so much! 🙇

[vy]

@pjfanning, you need to sign your commits. Could you do that, please? Otherwise, I cannot (am not allowed to) merge it.

[pjfanning]

I have opened an issue with GitHub - it could take a while. They are marking my signed commits as unverified and it's not clear why. I will close this. Feel free to reuse my code yourself. I place this code in the public domain.

It could be down to the fact that my git commits use my noreply GitHub email address instead of my real email address but I don't want to expose the real email address.

[vy]

Thanks @pjfanning! Cherry-picked your stuff in 468ab8c.