Visual Studio adds GitHub Copilot unit testing for C#

Microsoft has made GitHub Copilot testing for .NET, a new capability in GitHub Copilot Chat that automates the testing of C# code, generally available in the just-released Visual Studio 2026 v18.3 IDE.

Microsoft announced the capability on February 11.

GitHub Copilot testing for .NET automates the creation, running, and testing of C# code for projects, files, classes, or members. It has built-in awareness of the developer’s solution structure, test frameworks, and build system and operates as an end-to-end testing workflow rather than a single-response prompt, Microsoft said. GitHub Copilot testing for .NET can generate tests for the xUnit, NUnit, and MSTest test frameworks.

When prompted with a testing request, GitHub Copilot testing generates unit tests scoped to the selected code, builds and runs the tests automatically, detects failures and attempts to fix them, and reruns the tests until a stable starting point is reached, according to Microsoft.

When test generation is completed, GitHub Copilot provides a structured summary to help developers understand what has been changed, Microsoft said. This summary includes test files and projects completed or modified, before-and-after coverage information, pass/fail signals and unstable cases, insights into testability gaps, and direct links to the generated tests for immediate review and iteration.

Additionally, GitHub Copilot testing for .NET now supports free-form prompting, making it easier for the developer to describe what to test. GitHub Copilot testing for .NET requires a paid GitHub Copilot license.