dotnet-testing-strategy Decision framework for choosing the right test type, organizing test projects, and selecting test doubles in .NET applications. Covers unit vs integration vs E2E trade-offs with concrete criteria, naming conventions, and when to use mocks vs fakes vs stubs. Out of scope: Test project scaffolding (directory layout, xUnit project creation, coverlet setup, editorconfig overrides) is owned by [skill:dotnet-add-testing]. Code coverage tooling and mutation testing are covered by [skill:dotnet-test-quality]. CI test reporting and pipeline integration -- see [skill:dotnet-gha-…