Test-driven development workflow with philosophy guide - plan → write tests → implement → validate

/tdd Test Driven Development Workflow Strict TDD workflow: tests first, then implementation. When to Use "Implement X using TDD" "Build this feature test first" "Write tests for X then implement" Any feature where test coverage is critical Bug fixes that need regression tests TDD Philosophy Overview Write the test first. Watch it fail. Write minimal code to pass. Core principle: If you didn't watch the test fail, you don't know if it tests the right thing. Violating the letter of the rules is violating the spirit of the rules. The Iron Law Write code before the test? Delete it. Start over. No exceptions: Don't keep it as "reference" Don't "adapt" it while writing tests Don't look at it Delete means delete Implement fresh from tests. Period. Red Green Refactor RED Write Failing Test Write one minimal test showing what should happen. Good: Clear name, tests real behavior, one thing. Bad: Vague name, tests mock not code. Requirements: One behavior Clear name Real code (no mocks unless unavoidable) Verify RED Watch It Fail MANDATORY. Never skip. Confirm: Test fails (not errors) Failure message is expected Fails because feature missing (not typos) Test passes? You're testing existing behavior. Fix test. Test errors? Fix error, re run until it fails correctly. GREEN Minimal Code Write simplest code to pass the test. Good: Just enough to pass. Bad: Don't add features, refactor other code, or "improve" beyond the test. Verify GREEN Watch It Pass MANDATORY. Confirm: Test passes Other tests still pass Output pristine (no errors, warnings) Test fails? Fix code, not test. Other tests fail? Fix now. REFACTOR Clean Up After green only: Remove duplication Improve names Extract helpers Keep tests green. Don't add behavior. Common Rationalizations Excuse Reality "Too simple to test" Simple code breaks. Test takes 30 seconds. "I'll test after" Tests passing immediately prove nothing. "Tests after achieve same goals" Tests after = "what does this do?" Tests first = "what should this do?" "Already manually tested" Ad hoc ≠ systematic. No record, can't re run. "Deleting X hours is wasteful" Sunk cost fallacy. Keeping unverified code is technical debt. "Keep as reference, write tests first" You'll adapt it. That's testing after. Delete means delete. "Need to explore first" Fine. Throw away exploration, start with TDD. "Test hard = design unclear" Listen to test. Hard to test = hard to use. "TDD will slow me down" TDD faster than debugging. Pragmatic = test first. "Manual test faster" Manual doesn't prove edge cases. You'll re test every change. Red Flags STOP and Start Over Code before test Test after implementation Test passes immediately Can't explain why test failed Tests added "later" Rationalizing "just this once" "I already manually tested it" "Tests after achieve the same purpose" "Keep as reference" or "adapt existing code" All of these mean: Delete code. Start over with TDD. Verification Checklist Before marking work complete: [ ] Every new function/method has a test [ ] Watched each test fail before implementing [ ] Each test failed for expected reason (feature missing, not typo) [ ] Wrote minimal code to pass each test [ ] All tests pass [ ] Output pristine (no errors, warnings) [ ] Tests use real code (mocks only if unavoidable) [ ] Edge cases and errors covered Can't check all boxes? You skipped TDD. Start over. When Stuck Problem Solution Don't know how to test Write wished for API. Write assertion first. Ask your human partner. Test too complicated Design too complicated. Simplify interface. Must mock everything Code too coupled. Use dependency injection. Test setup huge Extract helpers. Still complex? Simplify design. Workflow Execution Workflow Overview Agent Sequence Agent Role Output 1 plan agent Design test cases and implementation approach Test plan 2 arbiter Write failing tests (RED phase) Test files 3 kraken Implement minimal code to pass (GREEN phase) Implementation 4 arbiter Run all tests, verify nothing broken Test report Core Principle Each agent follows the TDD contract: arbiter writes tests that MUST fail initially kraken writes MINIMAL code to make tests pass arbiter confirms the full suite passes Execution Phase 1: Plan Test Cases Phase 2: Write Failing Tests (RED) Phase 3: Implement (GREEN) Phase 4: Validate TDD Rules Enforced 1. arbiter cannot write implementation code 2. kraken cannot add untested features 3. Tests must fail before implementation 4. Tests must pass after implementation Example Refactor Phase (Optional) After GREEN, you can add a refactor phase: