Too many warnings to be useful

[mathemancer]

Description

Currently, running the test suite generates 1126 warnings for me. This means any valid ones are missed, and it generally makes the output of the test suite pretty useless when run with -svv to see actual problems.

Expected behavior

The test suite should not generate this many warnings (maybe none)

We should use a combination of

• filtering warnings we expect (e.g., UserWarnings when we're testing our own warnings) in pytest
• filtering 3rd party warnings (e.g., DeprecationWarnings) in pytest
• cleaning up code that generates warnings to avoid causing them, or filtering them if needed.

To Reproduce

Run the test suite with -svv set. Witness the horror.

Additional context

Helpful links for how to deal with the warnings in pytest:

• https://docs.pytest.org/en/6.2.x/warnings.html
• https://docs.python.org/3/library/warnings.html?highlight=warnings#warnings.filterwarnings