testing-rules

Testing Rules — Aiyu Agent Kit

If it's not tested, it's broken. Test with purpose, not just coverage.

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🔴 CRITICAL: Testing Fundamentals

Test Pyramid

        /\
       /  \        E2E Tests (few, slow, expensive)
      /────\       — Critical user journeys only
     /      \      
    / Integ  \     Integration Tests (some, moderate)
   /──────────\    — Service interactions, DB queries
  /            \   
 /  Unit Tests  \  Unit Tests (many, fast, cheap)
/________________\ — Business logic, edge cases

Distribution target: 70% Unit / 20% Integration / 10% E2E

AAA Pattern (Arrange-Act-Assert)

def test_user_creation():
    # Arrange
    user_data = {"email": "[email protected]", "name": "Test User"}
    
    # Act
    result = create_user(user_data)
    
    # Assert
    assert result.is_success
    assert result.user.email == "[email protected]"

Naming Convention

# test_<unit>_<scenario>_<expected_result>
def test_create_user_with_valid_data_returns_success():
    ...

def test_create_user_with_duplicate_email_raises_error():
    ...

def test_create_user_with_empty_name_returns_validation_error():
    ...

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🟡 HIGH: Test Quality

What to Test

Category	Examples	Priority
Happy path	Valid inputs, normal flow	Must
Edge cases	Empty, null, boundary values	Must
Error handling	Invalid input, service down	Must
Concurrency	Race conditions, deadlocks	Should
Performance	Response time, throughput	Nice to have

What NOT to Test

• Framework/library internals
• Trivial getters/setters
• Third-party API behavior (mock it)

Mocking Best Practices

# ✅ GOOD — Mock external dependencies, test your logic
@patch('services.email.send_email')
def test_welcome_email_sent_on_registration(mock_send):
    register_user(user_data)
    mock_send.assert_called_once_with(
        to=user_data["email"],
        template="welcome"
    )

# ❌ BAD — Mocking the system under test
@patch('services.user.validate_email')
def test_registration(mock_validate):
    mock_validate.return_value = True  # Testing mock, not logic
    register_user(user_data)