dotnet-add-testing

Add test infrastructure scaffolding to an existing .NET project. Creates test projects with xUnit, configures code coverage with coverlet, and sets up the conventional directory structure.

Scope

• Test project creation with xUnit and coverlet
• Conventional directory structure (tests/ mirroring src/)
• Project reference wiring and test SDK configuration

Out of scope

• In-depth testing patterns (xUnit v3, WebApplicationFactory, UI testing) -- see [skill:dotnet-testing-strategy]

Prerequisites: Run [skill:dotnet-version-detection] first to determine SDK version and TFM. Run [skill:dotnet-project-analysis] to understand existing solution structure.

Cross-references: [skill:dotnet-project-structure] for overall solution layout conventions, [skill:dotnet-scaffold-project] which includes test scaffolding in new projects, [skill:dotnet-add-analyzers] for test-specific analyzer suppressions.