Equipment Availability Improvements

[esoterik]

Inspired by recent issues with equipment availability checks.

We need more tests for availability, and some improvements to existing calculations to avoid situations like the one below.

Original

See here:

There's something weird happening, because the model only has one item and it is currently checked out and overdue; every column of the table is wrong.

Discovered while testing #1360

[orenyk]

Oh man, this is killing me. We need to go through all of the availability calculation code and test the heck out of it. Can you look into this so we can try to get it in v5.5.6?

[orenyk]

We just need a fix for v5.5.6, but we'll want comprehensive tests for master.

[esoterik]

sure, I'll look into it

[esoterik]

Okay, I think this is more a consequence of the seed script creating future overdue reservations (#1263), because the reason we get a negative number is that a future reservation is checked out and flagged as overdue, so the calculation isn't wrong.

Should I add in a fix to show 0 instead of a negative number or should I just close this issue

[orenyk]

Hmmm, should we instead ignore future reservations when calculating availability? Either way we can just lower bound the number at zero, but let's see if we can make the calculations "more correct". Either way, I say we take the opportunity to add some good test coverage 😄 - let's bump this to v6.0.0 and do that.

[esoterik]

Okay great