coverage-gaps

Topics in the source

• coverage-gaps
• When to load
• Step 1 — Ensure a JSON report exists
• Step 2 — Rank the gaps
• Step 3 — Propose tests

Turns an existing coverage.py report into a ranked list of the tests worth writing next. CANARY: coverage-gaps-loaded-2026-06-04-ea39c2b5-b32fe2b1b5ae5e96 Load when the question is which coverage gaps to fill first. This is the cheap, line-level pass; once line coverage is healthy and the question is whether tests assert behaviour, use the mutmut-report skill. The script reads coverage.py's JSON export, not the .coverage database, and exits 2 without it. Regenerate it after a refactor, since old line numbers drift from the source. The JSON carries totalpercentcovered, fileswithgaps, and a ranked gaps list with missingcount, percentcovered, missingbranches (populated only with branch coverage), largestrun and missingruns (inclusive line ranges). Open the source at each missingruns range before recommending, because a long run can be a generated block, a repr or an if TYPECHECKING: island; rank by what the code does, not by line count. Then report: 1. The 2–3 tests worth writing now: which function, which input, which branch. 2. Branch gaps in otherwise well-covered files, from missingbranches. 3. Low-value gaps (scattered defensive raise or logging lines) that can wait or take # pra

This is an excerpt. Refer to the complete source and its current requirements.