add-unit-testlisted

# Add a unit test Add focused, behaviour-asserting unit tests for the unit named in the ticket — matching the repo's existing test framework and conventions, not introducing a new one. ## Steps 1. **Find the unit + its existing tests.** Locate the source file and any sibling test file. Read 1–2 existing tests in the repo to copy the framework, naming, and assertion style (Vitest/Jest/pytest/JUnit — use what's already there). 2. **Enumerate behaviours to cover** from the ticket/AC: the happy path, each meaningful branch, boundary values, and the error/throws cases. Prefer behaviour ("returns empty array when no match") over implementation detail. 3. **Write tests** in the repo's test location and naming convention, one assertion focus per test, Arrange-Act-Assert. No test without a real assertion; no over-broad mocks that assert nothing. 4. **Run the test command** (use the repo's `test` script — see the context packet's verification commands). Iterate until green. If a test reveals a real bug, note it; fix only what the ticket scopes. 5. **Evidence:** the test command + its passing summary, and the new test file paths. Then use the `record-evidence` skill to record `test_output` against the AC and submit for review. ## TypeScript specifics - **Async functions:** `await` the call and assert on the resolved value, or use `await expect(fn()).rejects.toThrow(...)` for the failure path — never leave a floating promise, or the test passes befo