Date value field validation

[discopatrick]

This pull request is for issue #2513 (Date-valued field queries allow non-date values).

Period.parse() now raises a InvalidQueryArgumentTypeError when the string does not parse to a date - although I do wonder whether this is the correct error to raise, as I'm not comparing types here. I wonder whether a ValueError, or perhaps creating a new InvalidQueryArgumentValueError is more appropriate?

I have changed the way Period.parse() works - it used to first count the number of hyphens in the date to determine the precision (day, month, or year) and then try to parse the string against the appropriate date format. This did work fine. However, in anticipation of new feature #2506 (Extend the query date parser with (optional) times), where we will have '-', ':', and possibly ' ' or 'T' characters to count, I have opted for a different approach. I now test the string against each of the formats supported, from most precise to least precise, until a match is found (or not).

Tests have been updated to assert that the new errors are raised.

The output of a bad date query now reads quite nicely in the output:

$ beet list added:2017-01..2017-aa
invalid query: 'added:2017-01..2017-aa': '2017-aa' is not a valid datetime string

Finally, I have fixed a couple of older tests which were attempting to test mtime queries with an odd looking value of 0.0 and updated them to correct values.

tox passes all tests.

[mention-bot]

@discopatrick, thanks for your PR! By analyzing the history of the files in this pull request, we identified @sampsyo, @pkess and @diego-plan9 to be potential reviewers.

[sampsyo]

Yay! Thanks for getting this started!

Period.parse() now raises a InvalidQueryArgumentTypeError when the string does not parse to a date - although I do wonder whether this is the correct error to raise, as I'm not comparing types here. I wonder whether a ValueError, or perhaps creating a new InvalidQueryArgumentValueError is more appropriate?

Sure. In fact, I think we only use this exception as more akin to ValueError, not TypeError. So perhaps we should just rename the exception.

I have changed the way Period.parse() works -

Would you mind putting this refactoring into a separate pull request? Having one logical change at a time makes things a lot easier to review.

[discopatrick]

Sure @sampsyo, I'm splitting into two pull requests now.

I will leave the renaming of the exception to yet another pull request, to keep things tidy.

[sampsyo]

Awesome; thanks! ✨ I merged this one with a changelog entry.