tdd-morphic

name	tdd-morphic
description	TDD workflow for Morphic-Agent's 4-layer Clean Architecture. RED → GREEN → REFACTOR, placing tests and impls in the correct layer directories.
when_to_use	When implementing any new domain entity, use case, port, or infrastructure impl. Invoke before writing production code.
allowed-tools	["Read","Write","Edit","Bash(uv run pytest *)","Bash(ruff check *)","Grep","Glob"]
model	sonnet

TDD for Morphic-Agent

You execute the RED → GREEN → REFACTOR loop while respecting Morphic's layer boundaries.

Layer → Test location map

Code layer	Test folder
domain/entities/	tests/unit/domain/test_entities.py
domain/services/	tests/unit/domain/test_<service>.py
domain/ports/	No tests (ABCs only)
application/use_cases/	tests/unit/application/test_<use_case>.py (mock ports)
infrastructure/*/	tests/integration/test_<impl>.py (real PG/Redis/Qdrant)
interface/api/routes/	tests/integration/test_api_<route>.py (TestClient)
interface/cli/commands/	tests/integration/test_cli_<cmd>.py

Workflow

RED

1. Read the spec / plan to understand intent.
2. Write the failing test in the correct folder.
3. Run:

   uv run --extra dev pytest tests/unit/<layer>/test_<name>.py -v
   

   Expect: FAIL with specific assertion error.
4. Confirm the test actually exercises the target. No false passes.

GREEN

1. Write the minimum code to pass the test.
2. No premature abstractions. No "future-proofing".
3. Re-run the test. Must pass.
4. Run the full unit suite to catch collateral damage:

   uv run --extra dev pytest tests/unit/ -v
   

REFACTOR

1. Only if tests pass. Otherwise fix first.
2. Remove duplication.
3. Name things correctly.
4. Split long functions.
5. Re-run all unit tests.
6. Lint:

   uv run --extra dev ruff check .
   

Layer-specific rules

• Domain tests: zero imports from infrastructure/ or application/. Use plain pytest, no TestClient, no DB.
• Application tests: mock all ports with unittest.mock.AsyncMock or a hand-rolled in-memory port. Never real DB.
• Infrastructure integration tests: require docker compose up. Skip with pytest.importorskip for external services.

Commit cadence

After each GREEN, make a micro-commit:

git add <only changed files>
git commit -m "tests(<layer>): add <what>" -m "then" -m "feat(<layer>): implement <what>"

(or two separate commits).

Output

# TDD <feature>

## RED
- Test: tests/unit/<...>/test_<...>.py::test_<name>
- Failure: <assertion>

## GREEN
- Impl: <file>:<line>
- Passing: <N>/<N> tests

## REFACTOR
- Changes: <summary>
- Lint: clean

Guardrails

• Never skip RED. Writing code first and tests after is not TDD.
• Never mock in integration tests. If you find yourself mocking, it's a unit test — move it.
• Never commit red. Pre-commit hook should catch this.