Testing and Coverage

CI runs Rust, Python, and TypeScript tests plus lint/type checks. Coverage is orchestrated in justfile with direct CLI calls, using ninja only to prepare generated build artifacts that the test commands need.

Quick reference

just test                        # run all tests (no coverage)
just test --coverage             # run all tests + enforce coverage thresholds
just test --coverage --html      # same + generate HTML reports under out/coverage/

just test-rust                   # Rust only
just test-rust --coverage
just test-rust --coverage --html

just test-py                     # Python (pylib + qt) only
just test-py --coverage
just test-py --coverage --html

just test-ts                     # TypeScript/Svelte Vitest only
just test-ts --coverage
just test-ts --coverage --html

HTML reports are written under out/coverage/ (gitignored).

Coverage tools and thresholds

Stack	Test runner	Coverage tool	Minimum
Rust workspace	`cargo nextest` via `cargo-llvm-cov`	`cargo-llvm-cov`	60%
Python `pylib/anki`	`pytest pylib/tests`	`coverage.py`	65%
Python `qt/aqt`	`pytest qt/tests`	`coverage.py`	20%
TypeScript/Svelte	`vitest run`	Vitest V8	5%

Linux pull requests run just test --coverage in CI. macOS and Windows jobs run just test (no coverage enforcement) for now.

Notes

Rust — cargo-llvm-cov is installed on demand into out/bin/ to avoid polluting the global cargo install. Coverage runs rebuild the workspace with instrumentation, so they are slower than plain just test-rust. Windows ARM64 (aarch64-pc-windows-msvc) is not supported: the Rust compiler produces malformed .profraw files on that target (rust-lang/rust#150123, cargo-llvm-cov#436). just test-rust --coverage exits with a clear message on ARM64 Windows; use just test-rust (no coverage) or rely on CI (Linux) for enforcement.
Python — coverage is split across two suites (pylib and qt) because they have different PYTHONPATH setups and test folders.
TypeScript — coverage is measured only over code reachable through Vitest's module graph. Svelte component rendering behavior is not covered.

Gaps and future improvements

Raise thresholds gradually as the test suite grows and CI timings stabilise.
Exclude generated files from coverage denominators where appropriate.
Publish out/coverage/ as a CI artifact so reviewers can browse HTML reports directly from a PR.
Consider diff/changed-file coverage once baselines are stable — it is a better enforcement mechanism for incremental improvement than whole-repo thresholds.
Add component or browser tests for Svelte UI surfaces if Svelte coverage is intended to cover rendered component behaviour.