Using pytest instead of builtin unittest

[psteinb]

pytest has become one often used standard library for unit testing or continuous integration as a whole. It offers tons of plugins and handy features while not requiring as much boilerplate code as the python builtin unittest module.

As long as the number of tests is small, I suggest to move to pytest. Please drop 👍 or 👎 to express your opinion or comment on this idea directly.

[psteinb]

I'll convert what I can in due course then and adapt the existing unit tests.