Testing and Delivering

Why Testing Matters

Testing ensures quality, catches bugs early, and builds confidence in your application.

Types of Testing

1. Unit Testing

Testing individual components in isolation.

// xUnit Example
[Fact]
public void Add_TwoNumbers_ReturnsSum()
{
    // Arrange
    var calculator = new Calculator();
    
    // Act
    var result = calculator.Add(5, 3);
    
    // Assert
    Assert.Equal(8, result);
}

2. Integration Testing

Testing how components work together.

3. Functional Testing

Testing the application from a user perspective.

4. Performance Testing

• Load testing
• Stress testing
• Scalability testing

5. Security Testing

• Vulnerability scanning
• Penetration testing
• Security audits

Test-Driven Development (TDD)

The TDD Cycle

1. Write a failing test (Red)
2. Write the minimum code to make it pass (Green)
3. Refactor the code (Refactor)
4. Repeat

Continuous Integration (CI)

CI Pipeline Steps

# GitHub Actions Example
name: CI Pipeline

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
      
      - name: Setup .NET
        uses: actions/setup-dotnet@v3
        with:
          dotnet-version: '10.0.x'
      
      - name: Restore dependencies
        run: dotnet restore
      
      - name: Build
        run: dotnet build --configuration Release
      
      - name: Run tests
        run: dotnet test --configuration Release --verbosity normal

Deployment and Delivery

Deployment Strategies

• Blue-Green Deployment: Two identical environments
• Canary Deployment: Gradual rollout to users
• Rolling Deployment: Update instances one by one
• Feature Flags: Toggle features on/off

Deployment Checklist

# Pre-Deployment
- [ ] All tests pass
- [ ] Code review completed
- [ ] Version number updated
- [ ] Database migrations ready

# Deployment
- [ ] Database backup created
- [ ] Application deployed
- [ ] Health check passes

# Post-Deployment
- [ ] Smoke tests run
- [ ] Monitoring active
- [ ] Logs checked