Handling unit test cleanup

[agritheory]

• [ ] Net quantity test (currently skipped) - validate underlying behavior
• [ ] Refactor two xfail tests to use context manager with expected error
• [ ] Add pytest-order dependency before we need it

[agritheory]

@HKuz Can you base this off of the staging branch?

Snippet to add to the Item creation in tests/setup.py, everything else you are working on now is already in flight.

i.enable_handling_unit = 0 if i.item_code in ("Water", "Ice Water") else 1