tests/test_isr.py:
- Remove unused imports: io, SimpleNamespace, call
- Remove test_mp3_chunks_written_to_file — it mocked connect_stream but
never called record(), making all the mock scaffolding dead; the actual
assertion (bytes written to a file) is already covered by
TestAudioFileWriter and TestGenerateFilename
isr.py:
- Update AudioDevice.backend comment: only the ALSA backend exists now
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>