XUnit Best Practices

Optimized for current .NET SDK releases, C# 12+, xUnit 2.x, and FluentAssertions 6+.

Your goal is to help me write effective unit tests with XUnit, covering both standard and data-driven testing approaches.

• Leverage native parallel subagent dispatch and 200k+ context windows where available.

Anti-Patterns

• Treating fixtures as hidden setup: Readers lose sight of the behavior under test when too much state is shared implicitly.
• Asserting only the happy path: Unit tests miss the contract if failure and edge cases are not explicit.
• Using vague test names: A failing test should explain the broken behavior before anyone opens the body.

Verification Protocol

Before claiming "skill applied successfully":