Tdd

Test-Driven Development Workflow

Follow the TDD cycle for implementing changes.

The TDD Cycle

1. Write a Failing Test

Create an integration test that describes the expected behavior:

describe('Feature Name', () => {
  describe('Success Cases', () => {
    test('should do expected thing', async () => {
      const response = await request(app).get('/api/endpoint')
      expect(response.status).toBe(200)
      expect(response.body).toMatchObject(expectedData)
    })
  })

  describe('Failure Cases', () => {
    test('should fail when invalid input', async () => {
      const response = await request(app).get('/api/endpoint?invalid=true')
      expect(response.status).toBe(400)
    })
  })
})

2. Verify It Fails

Run the test to confirm it fails for the right reason:

npm test -- --testPathPattern="test-file-name"

3. Write Minimum Code to Pass

Implement only what's needed to make the test pass. No more.

4. Verify It Passes

Run the test again to confirm it passes.

5. Repeat

Continue the cycle for the next piece of functionality.

Guidelines

• Follow testing guidelines at .claude/guidelines/testing.md
• Use Minimum Sufficient Testing (MST) - don't over-test
• Integration tests with real HTTP requests (Jest + Supertest)
• Test success cases and all expected failure scenarios
• Favour editing existing tests over creating new ones