tdd-strict

name	tdd-strict
description	Use when high-assurance reliability is required (Bug fixes, Critical Features, Quality Hardening).
tier	3
version	1

Strict TDD Protocol (High Assurance)

This skill enforces a rigorous, evidence-based TDD cycle designed to eliminate "lucky passes" and "code hallucinations". It is stricter than the standard tdd-stub-first.

[!IMPORTANT] ACTIVATION: This skill replaces the standard TDD cycle. When active, you MUST follow the Strict Cycle below.

1. The Strict Cycle (Red-Red-Green-Refactor)

You must strictly follow this 4-step loop for EVERY test case.

Step 1: Write Test + EXPECTED_FAIL_REASON

Write the test case (or stub) and explicitly comment what exact error it should raise.

• Why: Prove that you know why it fails.
• Example:

  # EXPECTED_FAIL_REASON: AssertionError: Expected 200 OK, got 404 because endpoint is not registered.
  def test_create_user(client):
      resp = client.post("/users", json={"name": "Alice"})
      assert resp.status_code == 200
  

Step 2: Verify Fail (The "Red" Check)

Run the test. It MUST FAIL.

1. Check: Does the actual error match EXPECTED_FAIL_REASON?
2. Pass (on Fail): If it fails as expected -> Proceed.
3. Fail (on Logic): If it crashes with SyntaxError or ImportError -> Fix the test, do not touch code.
4. Fail (on Pass): If the test passes immediately -> STOP. You have a Logic Leak or a bad test. Delete code and investigate.

Step 3: Minimal Code Implementation (The "Minimalism Law")

Implement ONLY the code required to make the test pass.

• Prohibited: "While I'm here, I'll add the update method too."
• Prohibited: Adding generic exception handlers try: ... except: pass just to silence errors.
• Prohibited: Speculative architecture not required by the test.

[!CRITICAL] Dead Code Rule: If you write a line of code, ask: "If I delete this line, will the current test fail?" If the answer is No, DELETE IT.

Step 4: Verify Pass + EXPLAIN_PASS_REASON

Run the test. It MUST PASS.

1. Log: Explicitly state why it passed now.
   • Example: "PASS: Validated that registration logic now writes to DB returning 200."
2. Refactor: Now (and only now) you may clean up the code.

2. Red Flags (Stop Conditions)

• 🚩 Lucky Pass: You wrote a test and it passed immediately. STOP. Investigate why your test is ineffective.
• 🚩 Speculation: You are writing code for a "future requirement" not covered by the current failing test. STOP. Delete it.
• 🚩 Silent Failures: You saw a failure, didn't check the reason, and started coding. STOP. Verify the reason first.

3. Usage Context

• When to use:
  • Implementing Critical Core Features.
  • Fixing Bugs (Regression prevention).
  • When explicitly instructed to use "Strict Mode".
• When NOT to use:
  • Exploratory Prototyping (Spikes).
  • Initial Project Bootstrapping (creating large empty class structures).