Description

The TDD workflow ensures high-quality implementation by enforcing a cycle of writing tests before code. This skill guides the agent to break down implementation tasks into small, verifiable steps, ensuring each step is verified by a test before moving forward.

When to use this skill

• When the user asks to "implement" a feature or function.
• When the user agrees to a plan that involves coding.
• When you are about to use the TodoWrite tool for a coding task.
• When the user explicitly mentions "TDD" or "test driven".

Process

1. Plan with Todos: Before coding, create a TodoWrite list where every implementation step is paired with a verification step (test).
2. Red (Write Test): Create or update a test case that defines the expected behavior for the next small unit of work. Run it to confirm it fails (or verify it doesn't exist yet).
3. Green (Implement): Write the minimum code necessary to pass the test.
4. Verify: Run the test again to confirm it passes.
5. Refactor (Optional): Clean up the code if needed, ensuring tests still pass.
6. Repeat: Mark the todo item as done and move to the next pair of Test/Implement steps.

Examples

Example Todo List Structure

When implementing a RealInfluxClient:

Todos:
1. RED: Write integration test for RealInfluxClient.health() with testcontainers
2. GREEN: Implement RealInfluxClient.health() to make test pass
3. VERIFY: Run test and ensure it passes
4. RED: Write integration test for RealInfluxClient.write_tick()
5. GREEN: Implement RealInfluxClient.write_tick()
6. VERIFY: Run test and ensure it passes
7. RED: Write integration test for RealInfluxClient.query_ticks()
8. GREEN: Implement RealInfluxClient.query_ticks()
9. VERIFY: Run test and ensure it passes

Example Interaction

User: "Implement a function to reverse a string."

Agent: "I will use TDD to implement this. I'll start by creating a plan."

Calls TodoWrite:

1. RED: Create test case test_reverse_hello expecting "olleh"
2. GREEN: Implement reverse_string function to pass the test
3. VERIFY: Run tests to verify

Agent: "I've created the plan. First, I'll write the failing test." Writes test, runs it (fails). "Now I will implement the logic." Writes code, runs test (passes).