The current doctests only check a single valid output. You should add…The current doctests only check a single valid output. You should add tests for the validation logic implemented above, and also check "neutral" cases for filters with gain.

The current doctests only check a single valid output. You should add…The current doctests only check a single valid output. You should add tests for the validation logic implemented above, and also check "neutral" cases for filters with gain. #16487