TDD Workflow

Name: tdd-workflow
Rating: 92
Author: noooooooooooooooob

Write tests first, code second.

The TDD Cycle

code

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

The Three Laws

•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

RED Phase

What to Test

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

Rules

•Test MUST fail first
•Test name describes expected behavior
•One assertion per test (ideally)

GREEN Phase

Minimum Code

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

Rules

•Don't write unneeded code
•Don't optimize yet
•Pass the test, nothing more

REFACTOR Phase

What to Improve

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

Rules

•All tests must stay green
•Small incremental changes
•Commit after each refactor

AAA Pattern

Every test follows:

code

ARRANGE → Set up test data
ACT     → Execute code under test
ASSERT  → Verify expected outcome

When to Use TDD

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

Test Prioritization

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

Anti-Patterns

❌ Don't	✅ Do
Skip 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

Unity Testing

Edit Mode Tests

•Fast, no scene required
•Pure logic testing
•Use for: calculations, data validation

Play Mode Tests

•Requires scene
•Tests MonoBehaviour lifecycle
•Use for: integration, game flow

csharp

[Test]
public void Damage_ReducesHealth()
{
    // Arrange
    var unit = new Unit { Health = 100 };

    // Act
    unit.TakeDamage(30);

    // Assert
    Assert.AreEqual(70, unit.Health);
}

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