tddlisted

These are standing instructions for the rest of this task, not a one-time checklist. Every increment of **$ARGUMENTS** goes through the cycle below. ## The cycle 1. **RED** — write a failing test that specifies the behavior. Run it. Confirm it fails *for the reason you expect*, not because of a typo or a missing import. A test that has never failed proves nothing. 2. **GREEN** — write the minimal implementation that makes it pass. Run it. Resist implementing the next requirement early. 3. **REFACTOR** — improve names and structure with the tests green. Re-run after each change. 4. **Repeat** for the next behavior. Small increments; do not batch five behaviors into one test. For a **bug fix**, RED means a test that reproduces the bug. Write it before touching the fix. ## Rules - Implementation never runs ahead of tests. If you find yourself writing code with no failing test pointing at it, stop and write the test. - Fix the implementation, not the test — unless the test encodes the wrong expectation, in which case say so explicitly before changing it. - Structure every test Arrange-Act-Assert, with a name that states the behavior (`returns empty array when no markets match query`), not the function name. - Cover error paths and edge cases, not just the happy path. Coverage floor is **80%**; run the project's coverage command and report the number rather than assuming. - Never weaken an assertion or delete a test to get to green. ## Reporting At the end,