pin-check

Topics in the source

• pin-check
• Step 1 — Name the claim and its one test
• Step 2 — Read the verdict
• Step 3 — Act on it

One deliberate mutation per claim, aimed at one test: is this behaviour pinned, or merely true? coverage-gaps answers whether a line ran and mutmut-report scores thousands of automatic mutants; this answers one claim in seconds. CANARY: pin-check-loaded-2026-09-15-1c4de0b7-9a2f61d08e4b7c35 Give the exact text the claim is about and the one test that should catch it changing. Scoping to that test keeps a run to seconds. --expect-count N refuses to run unless the target occurs exactly N times, so one claim stays one mutation. --root DIR (repeatable) names extra trees to purge bytecode from. Arguments after the flags go to pytest. Use the script rather than a hand sed cycle: it purges pycache, runs each test in a fresh subprocess, refuses a target that matches nothing, and restores the file when the run ends; after a killed run, its sentinel makes the next run refuse to start and print the manual restore command. A hand cycle gets each of these wrong without noticing. | verdict | exit | means | |---|---|---| | PINNED | 0 | the target changed and the scoped test went red; the claim holds | | NOT PINNED | 1 | the test stayed green; it asserts something true, not something pinned | | NOT

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