Reword tests for clarity

[andylolz]

A number of the tests have docstrings that are very ambiguous.

It would be good to reword them, so it’s clearer exactly what the test is checking.

[andylolz]

@siemvaessen I’ve just clarified the wording a bit in 405d224:

[siemvaessen]

Nice. Although it is just a (random) margin and def. can not be labelled an error..

[andylolz]

It’s not labelled an error. It’s a smoke test – if there’s more than a 10% discrepancy, that suggests something might be wrong.

In this case, I think it worked – it correctly spotted something was wrong. It’s happy again now:

[andylolz]

If you can think of a better test here, I can have a go at updating this.

I think we’ll always need to allow for some margin of error, because sometimes publishers’ servers will have sporadic issues, so we want to be resilient to that sort of thing.