Guidelines for writing TUnit tests in .NET, including setup, assertions, async testing, and best practices. Use when writing unit tests with TUnit framework, setting up TUnit in a .NET project, or migrating from other test frameworks to TUnit.
Hosted services, background jobs, outbox patterns, and graceful shutdown handling for ASP.NET Core applications. Includes patterns for reliable job processing, distributed systems, and lifecycle management. Use when implementing background processing in ASP.NET Core applications, handling outbox patterns for reliable message delivery, or managing graceful service shutdown.
Design stable, compatible public APIs using extend-only design principles. Manage API compatibility, wire compatibility, versioning, naming conventions, parameter ordering, and return types for NuGet packages and distributed systems. Use when designing public APIs for NuGet packages or libraries, making changes to existing public APIs, planning wire format changes for distributed systems, or reviewing pull requests for breaking changes.
Write modern, high-performance C# code using records, pattern matching, value objects, async/await, Span<T>/Memory<T>, and best-practice API design patterns. Emphasizes functional-style programming with C# 12+ features. Use when writing new C# code or refactoring existing code, designing public APIs for libraries or services, optimizing performance-critical code paths, or building async/await-heavy applications.
Choosing the right concurrency abstraction in .NET - from async/await for I/O to Channels for producer/consumer to Akka.NET for stateful entity management. Covers both high-level abstractions and low-level synchronization primitives. Use when deciding how to handle concurrent operations in .NET, evaluating whether to use async/await, Channels, or Akka.NET, or managing state across multiple concurrent entities.
Design .NET types for performance. Covers struct vs class decision matrix, sealed by default, readonly structs, ref struct and Span/Memory selection, FrozenDictionary, ValueTask, and collection return types. Use when designing new types and APIs, reviewing code for performance issues, choosing between class, struct, and record, or working with collections and enumerables.
Building accessible .NET UI. SemanticProperties, ARIA, AutomationPeer, testing tools per platform.
Adding analyzer packages to a project. Nullable, trimming, AOT compat analyzers, severity config.