tdd

@tdd

Trigger: When building a new function, module, or feature from scratch, or reproducing a bug.

Protocol

Red phase — write failing tests

1. Read clarified scope from get_memory key=clarified-scope (if available).
2. Write tests that define the contract:
   • Happy path: normal inputs produce expected outputs
   • Edge cases: empty, null, boundary values, large inputs
   • Error cases: invalid inputs raise correct errors
3. Run the tests. All must fail (red). If any pass, the test is wrong — fix it.
4. Call update_mode_state mode=tdd-like phase=red (use deep-interview mode as proxy if tdd not registered).

Green phase — minimum implementation

1. Write the minimum code to make all tests pass.
2. Run tests. Iterate until green.
3. No over-engineering — if tests pass with 5 lines, write 5 lines.

Refactor phase — clean without breaking

1. Identify: duplication, poor naming, long functions, unclear logic.
2. Refactor — do NOT change observable behavior.
3. Run tests. Must still be green.

Commit

1. Two commits:
   • test: add tests for {feature}
   • feat: implement {feature}

Rules

• Tests before implementation — always, no exceptions.
• Never delete or skip tests to make them pass.
• Never modify tests in the green/refactor phase.
• If a test seems impossible to pass: the design may be wrong — revisit the interface.