test-driven-development

---

description: Enforce test-driven development with atomic steps and user verification at each stage globs: "**/*" alwaysApply: true

Test-Driven Development Rule

Enforce test-driven development practices with atomic steps and user verification.

actions:

• type: enforce message: | TEST-DRIVEN DEVELOPMENT PROTOCOL

  MANDATORY TDD WORKFLOW:

  1. ALWAYS START WITH TESTS:

     • Plan and write tests BEFORE writing implementation code
     • Create tests for every new feature, bug fix, or change
     • Follow Red-Green-Refactor cycle

  2. ATOMIC TEST STEPS:

     • Write ONE test at a time
     • Keep each test focused on a single behavior
     • Do not write long test suites all at once
     • Stop after each atomic test step

  3. USER VERIFICATION REQUIRED:

     • After writing each test, wait for user verification
     • Let user review and approve test before proceeding
     • Only continue to implementation after test approval
     • User must confirm each step before moving forward

  4. COVERAGE REQUIREMENTS:

     • Aim for full or near-full test coverage
     • Cover edge cases and error scenarios
     • Test both positive and negative paths
     • Document any untested code with clear reasoning

  5. FRAMEWORK DEPENDENCY:

     • Use testing frameworks specified by user
     • Follow user's testing patterns and conventions
     • Ask user to specify testing approach if unclear
     • Adapt to existing test structure in codebase

  6. INCREMENTAL APPROACH:

     • Small, verifiable steps only
     • No large code blocks without tests
     • Each implementation should make tests pass
     • Refactor only after tests are green

  7. CONTINUOUS TESTING:

     • Any change to src/ directory triggers all tests
     • Must ensure all tests pass before proceeding
     • Fix broken tests immediately
     • No code changes without verified test coverage

  WORKFLOW STEPS:

  1. Understand requirement
  2. Write failing test (Red)
  3. STOP - Get user verification
  4. Write minimal code to pass test (Green)
  5. RUN ALL TESTS - Ensure nothing breaks
  6. STOP - Get user verification
  7. Refactor if needed (Refactor)
  8. RUN ALL TESTS - Verify refactor didn't break anything
  9. STOP - Get user verification
  10. Repeat for next atomic feature

  AUTO-TEST TRIGGER:

  • Any file modification under src/ automatically runs: pytest tests/ -v
  • Must address any test failures before continuing development
  • Ensures continuous validation and early error detection

examples:

• input: | User: "Add a login function"

  Correct TDD approach:

  Step 1: "I'll write a test for login function first. Here's the failing test..." [Wait for user approval] Step 2: "Now I'll implement minimal code to make this test pass..." [Wait for user approval] Step 3: "Let's refactor and add the next test case..." output: "Following TDD with atomic steps and user verification"

• input: | User: "Fix the bug in calculation"

  Correct TDD approach:

  Step 1: "I'll write a test that reproduces the bug first..." [Wait for user approval] Step 2: "Now I'll fix the code to make the test pass..." output: "Bug fix following TDD principles"