Aspire Integration Testing

This one covers integration testing for .NET Aspire apps with xUnit, focusing on testing with real dependencies instead of mocks. You'll use it when you need to verify service-to-service communication, test against actual SQL Server or Redis in containers, or run Playwright UI tests against Aspire-orchestrated backends. The skill emphasizes dynamic port binding and endpoint discovery so tests don't conflict when running in parallel. There's a critical fix included for file descriptor exhaustion on Linux when running many tests. It's genuinely useful if you're building distributed .NET apps and want integration tests that don't feel like a maintenance nightmare.