Pyworking Testing materials

[hroncok]

First version is at https://github.com/pyvec/pyworking-materials/tree/master/180324_Testovani

Should we adapt it for here or not? There are already 2 lessons for testings. I don't want to introduce a third one without planning. Maybe spliting into multiple sections and combining those (i.e. betamax is a specific topic, it doesn't need to be part of MI-PYT's testing document directly).

The materials are bit like this horse at the end, but that can be solved given some time:

[encukou]

I think these questions are relevant:

• Do you want something naucse has over GitHub renderer? figure, solution, formatting, prev/next etc.
• Do you want to maintain this forever?
• Will it wait for Arca?

Note that from a naucse run you can link to arbitrary URLs. (Maybe we should make "externally hosted lesson" special, though.) The pyworking repo is nice for one-off "scratch courses"; naucse is meant for things available to others to replicate and improve.

Splitting Betamax out sounds like a good idea. So does splitting the pyworking materials.