csharp-testing

Design C# and .NET unit and integration testing practices with xUnit and FluentAssertions.

Updated May 11, 2026
One-click install
npx skills add https://github.com/CZ-X-Ya/oh-my-csharp-skills --skill csharp-testing-cz-x-ya
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: csharp-testing
Source: https://github.com/CZ-X-Ya/oh-my-csharp-skills/tree/main/csharp-testing
Command: npx skills add https://github.com/CZ-X-Ya/oh-my-csharp-skills --skill csharp-testing-cz-x-ya

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Poor or disorganized tests make C# and .NET teams ship slower, debug harder, and miss real regressions.

Core Features & Use Cases

  • Test framework and assertion patterns: Use xUnit with FluentAssertions for readable, intention-revealing checks.
  • Mocking and isolation techniques: Apply NSubstitute or Moq to control dependencies and verify behavior.
  • Integration testing with real infrastructure: Use WebApplicationFactory for ASP.NET Core and Testcontainers for databases to validate end-to-end behavior.
  • Practical test organization: Establish a consistent folder structure, test data builders, and anti-pattern avoidance to keep suites maintainable.

Quick Start

Activate this skill when you are writing or reviewing C# tests and want a clean approach using xUnit, FluentAssertions, and integration strategies with fixtures and builders.

Frequently Asked Questions about csharp-testing

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I organize xUnit tests in C# to avoid flaky and low-signal results?▼

Structure xUnit tests using clear folder organization, test data builders, and deterministic fixtures to prevent flaky or low-signal results. Arrange-act-assert patterns and FluentAssertions further enhance test readability and maintainability.

What is the best way to write readable C# unit test assertions?▼

Use FluentAssertions with xUnit to write readable, intention-revealing C# unit test assertions. This combination replaces rigid assertion syntax with fluent chains, improving test readability and maintainability.

How do I set up ASP.NET Core integration tests with WebApplicationFactory?▼

Use WebApplicationFactory to bootstrap your ASP.NET Core application in-memory for integration tests. Combine it with Testcontainers to provision real databases, validating end-to-end behavior against live infrastructure dependencies.

Does this C# testing approach work with NSubstitute or Moq for mocking dependencies?▼

Yes, this approach supports both NSubstitute and Moq for mocking dependencies. Apply either framework to control dependencies, isolate units, and verify interaction behavior during unit testing.

How do I write parameterized xUnit Theory tests in .NET?▼

Write parameterized xUnit Theory tests in .NET using the [Theory] attribute combined with [InlineData] or [MemberData]. This pattern executes a single test method across multiple data sets, reducing duplication.

When should I use Testcontainers instead of mocks for .NET integration tests?▼

Use Testcontainers instead of mocks for .NET integration tests when validating end-to-end behavior against real infrastructure. Testcontainers spin up actual databases, providing higher confidence than isolated mocks.