Reports - some tests

Two canned, one custom.

Could be better but I did not want to extend the UI coverage. There might be some issues with the report data comparison, I will be happy for feedback that I can eventually fix those.
Peeking at `__init__`'s docstring, if the second argument can be made by calling `queue_canned_report`, it seems like this method isn't needed. Have `__init__`'s `datetime` default to `None`, and if it's `None`, `self.datetime = queue_canned_report(*path)`

Then, wherever you're calling `.new` now, just make a new instance.