git:20260930.445fa69 to git:20260930.a77cb5e

---

name: write-test

description: >

Generate tests for existing code. Auto-triggers on:

"write tests for", "add test coverage", "this needs tests"

allowed-tools: Read, Write, Edit, Bash, Grep, Glob

---

# Write Tests

## 0. Detect the framework

- Run `devil facts` — it reports the detected test framework. Write in

THAT framework, in its idiom (see `rules/test-frameworks.md`). Don't introduce a

second framework; don't hand-roll asserts/mocks it already ships.

- None configured? Pick the canonical default for the stack and say why in one line.

## 1. Read the source

- Understand every public function's contract

- Identify edge cases from the implementation (not just happy path)

## 2. Design test cases (before writing any code)

For each function, list:

- Happy path (normal input → expected output)

- Boundary (empty, zero, max, nil/null)

- Error path (invalid input, resource failure)

- Concurrency (if the function touches shared state)

Present the test plan. Wait for approval.

## 3. Write

- Table-driven / parameterized tests in the detected framework's idiom (Go subtests, `rstest`, `it.each`, `pytest.mark.parametrize`)

- Property-based tests for anything parsing external input (Hypothesis, proptest, fast-check, `testing/quick`)

- One test function per behavior, not per source function

- Test names describe the scenario: `test_login_rejects_expired_token`

- No test depends on another test's state

- No sleep() — use channels, signals, or mocks

## 4. Verify

- All new tests pass

- All existing tests still pass

- No flaky tests (run 3 times)

- Report coverage delta