test: increasing unit test coverage to 95 percent - #740

Increase unit test coverage (~95%) + coverage in CI

Adds a hand-written custom test suite that raises deepgram package coverage to the ~95% target (branch coverage enabled), wires coverage reporting into CI with an automatic sticky PR comment, and scopes coverage to hand-maintainable logic rather than Fern-generated boilerplate. New tests and the coverage config are frozen in .fernignore so they survive the next SDK regeneration.

Coverage on the scoped source went from ~54% line / ~32% branch to 94.72% (gate fail_under = 90). No product code changed — this PR is tests + CI + config only.

What changed

• CI (.github/workflows/ci.yml)

  • Runs on pull_request in addition to push (push now scoped to main + tags).
  • Test step runs under coverage: pytest -rP --cov=deepgram --cov-branch --cov-report=xml --cov-report=term-missing .
  • Generates a coverage summary and posts/updates a sticky PR comment (Python 3.13 leg only); also writes it to the job summary. Fork PRs are skipped for the comment (read-only token) and the step is best-effort.
  • Grants the test job pull-requests: write (with contents: read) so it can comment.

• Coverage config (.coveragerc, not pyproject.toml)

  • [run] branch coverage on, source = deepgram, with pure-generated code excluded (types/, requests/, __init__.py, version.py, unused core/http_sse/) so the metric reflects code that carries logic.
  • [report] fail_under = 90, show_missing = True.
  • Kept out of pyproject.toml deliberately: freezing pyproject.toml would also block Fern's generator dependency updates.

• Dev dependencies (pyproject.toml)

  • Adds pytest-cov and respx (HTTP mocking) to the dev group.

• New tests (tests/custom/, ~170 test functions, many parametrized)

  • test_http_endpoints_coverage.py — table-driven sweep of REST endpoints (success + 400/403/non-JSON error branches, sync + async).
  • test_http_retry_coverage.py — retry/backoff behavior (exponential backoff, Retry-After, Retry-After-ms, X-RateLimit-Reset, exhaustion).
  • test_websocket_streaming_coverage.py — websocket streaming clients.
  • test_speak_v2_coverage.py — Speak V2 (Flux TTS): batch REST audio.generate streaming, connect header/handshake-failure branches, socket-client iteration/send/recv. Raises speak.v2 from 44% → 97%.
  • test_core_internals_branches.py, test_core_utilities_coverage.py, test_client_construction_and_helpers.py, test_logging_and_retry_branches.py — core utilities, client construction, logging/retry, and remaining branch gaps.

• Regen safety / housekeeping

  • .fernignore — freezes the 8 new custom test files, .coveragerc, and .gitignore. Documented in AGENTS.md.
  • .gitignore — ignores .coverage, htmlcov/, coverage.xml (and the previously-tracked .coverage artifact is now untracked).
  • Rebased onto latest main (7.7.0 regen) to keep the branch current.

Testing

• New tests use respx (HTTP) and in-process websocket fakes — no network / no WireMock dependency.
• Full suite: 981 passed, 1 skipped under coverage locally; CI runs the full suite on Python 3.10–3.13.

Open item (for @greg / Fern pipeline): pyproject.toml is intentionally unfrozen, but now carries the respx / pytest-cov dev deps the frozen tests need. Confirm these survive the next Fern pyproject.toml regen (or move them into the generator's dependency config) so the frozen suite doesn't break on a future regen.