tdd-workflow

Test-Driven Development workflow principles. RED-GREEN-REFACTOR cycle.

name:tdd-workflowdescription:Test-Driven Development workflow principles. RED-GREEN-REFACTOR cycle.allowed-tools:Read, Write, Edit, Glob, Grep, Bash

TDD Workflow

> Write tests first, code second.

1. The TDD Cycle

🔴 RED → Write failing test
    ↓
🟢 GREEN → Write minimal code to pass
    ↓
🔵 REFACTOR → Improve code quality
    ↓
   Repeat...

2. The Three Laws of TDD

Write production code only to make a failing test pass

Write only enough test to demonstrate failure

Write only enough code to make the test pass

3. RED Phase Principles

What to Write

Focus	Example
Behavior	"should add two numbers"
Edge cases	"should handle empty input"
Error states	"should throw for invalid data"

RED Phase Rules

Test must fail first

Test name describes expected behavior

One assertion per test (ideally)

4. GREEN Phase Principles

Minimum Code

Principle	Meaning
YAGNI	You Aren't Gonna Need It
Simplest thing	Write the minimum to pass
No optimization	Just make it work

GREEN Phase Rules

Don't write unneeded code

Don't optimize yet

Pass the test, nothing more

5. REFACTOR Phase Principles

What to Improve

Area	Action
Duplication	Extract common code
Naming	Make intent clear
Structure	Improve organization
Complexity	Simplify logic

REFACTOR Rules

All tests must stay green

Small incremental changes

Commit after each refactor

6. AAA Pattern

Every test follows:

Step	Purpose
Arrange	Set up test data
Act	Execute code under test
Assert	Verify expected outcome

7. When to Use TDD

Scenario	TDD Value
New feature	High
Bug fix	High (write test first)
Complex logic	High
Exploratory	Low (spike, then TDD)
UI layout	Low

8. Test Prioritization

Priority	Test Type
1	Happy path
2	Error cases
3	Edge cases
4	Performance

9. Anti-Patterns

❌ Don't	✅ Do
Skip the RED phase	Watch test fail first
Write tests after	Write tests before
Over-engineer initial	Keep it simple
Multiple asserts	One behavior per test
Test implementation	Test behavior

10. AI-Augmented TDD

Multi-Agent Pattern

Agent	Role
Agent A	Write failing tests (RED)
Agent B	Implement to pass (GREEN)
Agent C	Optimize (REFACTOR)

> Remember: The test is the specification. If you can't write a test, you don't understand the requirement.

tdd-workflow - Agent Skills