add test suite

[palakpsheth]

Overview

This PR adds a full pytest-based unit test suite for subgen.py and wires up CI to run those tests with coverage. The tests are designed to maximize coverage while avoiding heavy runtime dependencies by using lightweight stubs for external libraries (FastAPI, stable-whisper, ffmpeg/av, requests, watchdog, torch).

Key changes

• Added tests/conftest.py with dependency stubs + a subgen_module fixture that:
  • disables background threads (CONCURRENT_TRANSCRIPTIONS=0) and filesystem monitor
  • injects stub modules to avoid importing GPU/FFmpeg/HTTP dependencies
  • keeps import side effects deterministic and fast
• Added tests/test_subgen.py with broad coverage for:
  • env helpers (convert_to_bool, get_env_with_fallback)
  • queueing logic (DeduplicatedQueue)
  • webhook handlers (Tautulli/Plex/Jellyfin/Emby) with path mapping
  • ASR + detect-language handlers
  • subtitle naming, skip logic, and language selection
  • audio/subtitle helpers (track parsing, subtitle discovery, audio extraction)
  • miscellaneous helpers (path mapping, file stability, has_audio, etc.)
• Added pytest.ini to ensure repo root is on PYTHONPATH
• Added .github/workflows/tests.yml to run pytest on push/PR and upload coverage.xml
• Updated .gitignore to keep __pycache__, *.pyc, and coverage artifacts out of git

Testing

• pytest -q --cov=subgen --cov-report=term-missing --cov-report=xml

Coverage

• CI uploads coverage.xml as an artifact.
• Coverage focuses on subgen.py execution paths; external dependencies are stubbed, so this does not validate real FFmpeg/AV/Whisper integrations.

Notes / limitations

• The tests are intentionally unit-level and avoid network access or real media processing.
• Integration behavior with real media files, FFmpeg/AV, and Whisper models is not covered here.

[Copilot]

Pull request overview

This PR adds a comprehensive test suite for the subgen project using pytest. The test suite includes 57 test cases covering various functionality of the subtitle generation system, from webhook handling to audio processing and file operations.

Changes:

• Added comprehensive pytest-based test suite with 57 test cases
• Implemented GitHub Actions CI workflow for automated testing
• Added pytest configuration and updated .gitignore for test artifacts

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/test_subgen.py	Implements 57 test cases covering core functionality including webhooks, audio processing, subtitle generation, and file operations
tests/conftest.py	Provides pytest fixture that stubs all heavy dependencies (fastapi, stable-whisper, ffmpeg, etc.) allowing tests to run with minimal dependencies
pytest.ini	Configures pytest with pythonpath to enable imports from project root
.gitignore	Adds Python test artifacts (pycache, .coverage, coverage.xml, htmlcov/)
.github/workflows/tests.yml	Sets up CI pipeline with Python 3.11, runs pytest with coverage reporting, and uploads coverage artifacts

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