Unit tests

[azmeuk]

This patch:

• Adds a DNSServer class in dnserver.py. It has a simple interface like server.start(), server.stop() and server.is_running. I hope this can be used as a dns server fixture in other projects.
• Adds a tox configuration for currently active python versions.
• Adds a simple unit test, that just makes a request to the DNS.
• Adds a GHA configuration, for safety.
• Requires dnslib 0.9.20
• It refactors the code so it uses zone strings instead of zone path, so it is easier to use in a python context.

@samuelcolvin

[samuelcolvin]

Hi really happy to get this to a point where it can be released to pypi, including unit tests.

I would prefer not to use tox, but rather rely on github actions to test on multiple versions - this is mostly because it's the workflow I know best and can therefore support most easily.

Could you refactor this to follow the example of dirty_equals? If there are bits you find confusing, feel free to leave a comment on this PR and omit them.

[azmeuk]

I removed tox and adapted the GHA yaml config file following what I could read in dirty_equal. I am curious how do you test several python versions on your development machine without tox?

At first I intended to plug pre-commit and some style tools like black, but I thought this would be better in another PR.

[samuelcolvin]

I removed tox and adapted the GHA yaml config file following what I could read in dirty_equal. I am curious how do you test several python versions on your development machine without tox?

I have multiple virtualenvs, and if I really need to test between versions quickly, I activate each in a different terminal; but mostly it's not necessary.

At first I intended to plug pre-commit and some style tools like black, but I thought this would be better in another PR.

Sounds good.

[samuelcolvin]

not sure what this is doing, but I think it shouldn't be there.

[azmeuk]

yamllint yells when this is absent

[samuelcolvin]

I'll merge and check what github thinks, it definitely doesn't have to be there.

[samuelcolvin]

thanks so much, I'll make further changes in a new PR.