| name | bug-fix-tdd |
| description | Enforce test-first workflow for bug fixes. Use whenever the user asks to fix a bug, defect, regression, or issue. Write a failing test that captures the bug AND a passing test for the correct behavior BEFORE touching production code, then fix and flip. |
Bug-fix TDD
When asked to fix a bug/issue/regression, follow this sequence. Do not skip steps.
1. Write tests first (before any production change)
Add two test cases:
- bug_case: asserts the CURRENT (broken) behavior. Passes today, will fail after the fix.
- fix_case: asserts the CORRECT behavior. Fails today, will pass after the fix.
Run the suite. Confirm: bug_case passes, fix_case fails. If this isn't true, you haven't reproduced the bug — stop and re-examine.
2. Apply the fix
Change production code only. Do not edit tests in this step.
3. Flip and verify
Run the suite. Expected result: fix_case passes, bug_case fails.
Now invert bug_case so it asserts the post-fix behavior (i.e. that the broken behavior no longer occurs). The final committed state must have both tests passing and both guarding against regression.
Rules
- Never write the fix before the tests.
- Never delete
bug_case — flip its assertion so it stays as a regression guard.
- If you can't write a failing test, say so explicitly and ask the user how to proceed. Don't fix blind.
