D19 Comments and Diff

[Kamil Paral]

> That being said, I don't really want to start off with tests that are
> putting too many asserts into the one test. Some combinations are fine
> but I'd prefer erring on the side of separating things out a bit too
> much for now rather than risk setting an example of large, monolithic
> tests.

I agree, and it's especially important for more complex code. But in this case, I think I've hit the sweet spot. The tests are really simple, and therefore they can be clustered together (in a reasonable extent) for improved readability and reduced test code length.

By the way, I've pushed some more revisions of the patch. It contains 64 lines of code + 144 lines of documentation and whitespace, and 208 lines of code of tests. Pylint score is 100% and test coverage is 100%. I think it's my best code ever, by all metrics ;) Let's not be too nitpicky here.