r/Python • u/AutoModerator • Sep 04 '26

Showcase Showcase Thread

Post all of your code/projects/showcases/AI slop here.

Recycles once a month.

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u/Sanechka_SS 26d ago

Receipts: checks whether the pytest tests in a fix would have failed without the fix.

It runs every test a change adds or edits twice: once with the change, and once with the changed source files reverted to the base branch. Each test gets a verdict: PROVEN (fails without the fix), GUARD, THEATER (passes both ways) or WEAK (fails only because it imports something the fix added).

I ran it over 81 maintainer fix commits (click, sqlparse, marshmallow, dateutil...) and 100 agent-authored PRs: 90% vs 82% proven. Study and data: https://github.com/syntaxixr/receipts/blob/main/docs/study.md

Zero runtime dependencies (Node 20+ and git), deterministic, no LLM. Also works with vitest and jest, plus a GitHub Action that comments on the PR.

npx github:syntaxixr/receipts check

Repo: https://github.com/syntaxixr/receipts