Improve Coverage Accuracy and Speed Up Tests

[Darshan808]

Fixes #95

Description

Our coverage number was misleading. It reported ~16%, but that was because almost all of the real testing happens through subprocess.run(["jupyter-builder", ...]) calls, and coverage does not track subprocesses by default. The code was being tested, just not measured.

• Use coverage.py 7.10's patch = ["subprocess"], so the jupyter-builder and jlpm CLIs collect coverage themselves and pytest-cov merges everything into a single report.

Result: Coverage increased from ~16% → ~70% without changing any tests.

Faster tests

• Move the template clone, jlpm install, and TypeScript build into session-scoped fixtures (tests/conftest.py). Each test now gets a cheap local copy instead of repeating the expensive setup.
  • Before: 6 clones / 6 installs
  • After: 1 clone / 3 installs (one per template variant)
• Replace fixed sleeps in watch tests with polling for build output.
• Mark all tests in test_tpl.py as slow, so pytest -m "not slow" provides a much faster local test run.

[Darshan808]

Some progress here.
On ubuntu and MacOS runners, I see 70% coverage. But on windows runners I see 62% coverage.

[Darshan808]

The version mismatch test started to act flaky.

[Darshan808]

Ah, Test is being flaky as it is hitting rate limits when trying to pull core-meta from github.

(HTTP Error 403: rate limit exceeded)

[Copilot]

Pull request overview

This PR aims to (1) make CI coverage reporting accurate for code exercised via subprocess-driven CLI tests and (2) reduce test runtime by moving expensive template setup/build work into shared pytest fixtures.

Changes:

• Enable subprocess-aware coverage collection via coverage.py config (patch = ["subprocess"]) and re-enable the CI coverage gate.
• Speed up tests by introducing session-scoped fixtures that render/build the template once and provide per-test copies.
• Reduce watch-test flakiness by replacing fixed sleeps with polling, and mark template tests as slow.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/test_tpl.py	Refactors template/watch tests to use shared fixtures, adds polling for watch tests, and marks all tests as slow.
tests/conftest.py	Adds session-scoped fixtures to render/build/install the template once and provide isolated per-test copies; sets COVERAGE_FILE.
pyproject.toml	Updates test dependencies and adds coverage + pytest marker configuration to support subprocess coverage and slow marker.
jupyter_builder/debug_log_file_mixin.py	Fixes empty-path directory handling for debug logs and broadens best-effort unlink suppression for Windows.
.github/workflows/builder-tests.yml	Re-enables the coverage job to enforce a minimum coverage threshold in CI.

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