C# Testing Patterns
Comprehensive testing patterns for .NET applications using xUnit, FluentAssertions, and modern testing practices.
When to Activate
- Writing new tests for C# code
- Reviewing test quality and coverage
- Setting up test infrastructure for .NET projects
- Debugging flaky or slow tests
Test Framework Stack
| Tool | Purpose |
|---|---|
| xUnit | Test framework (preferred for .NET) |
| FluentAssertions | Readable assertion syntax |
| NSubstitute or Moq | Mocking dependencies |
| Testcontainers | Real infrastructure in integration tests |
| WebApplicationFactory | ASP.NET Core integration tests |
| Bogus | Realistic test data generation |
Unit Test Structure
Arrange-Act-Assert
public sealed class OrderServiceTests
{
private readonly IOrderRepository _repository = Substitute.For<IOrderRepository>();
private readonly ILogger<OrderService> _logger = Substitute.For<ILogger<OrderService>>();
private readonly OrderService _sut;
public OrderServiceTests()
{
_sut = new OrderService(_repository, _logger);
}
[Fact]
public async Task PlaceOrderAsync_ReturnsSuccess_WhenRequestIs…
