migrate-xunit-to-mstest

name	migrate-xunit-to-mstest
description	Convert .NET test projects from xUnit.net v2 or v3 to MSTest v4. Use for replacing xunit packages, [Fact]/[Theory], xUnit assertions, fixtures, ITestOutputHelper, traits, skips, and xUnit parallelization with MSTest equivalents while preserving the current VSTest or MTP runner. DO NOT USE FOR: xUnit v2 to v3 upgrades, MSTest version upgrades, migrations from NUnit/TUnit, or runner-only VSTest to MTP migrations.
license	MIT

xUnit -> MSTest Migration

Convert xUnit.net v2 or v3 tests to MSTest v4 without changing the target framework or test platform. A successful migration builds, discovers the same tests, and preserves pass/fail results and execution semantics.

Scope

Use this skill only when the project contains xUnit packages or source and the user wants MSTest. If the project already uses MSTest and contains no xUnit tests, report that no framework migration is needed and make no changes.

Do not combine this framework conversion with a target-framework upgrade or VSTest/MTP migration. Complete and verify one migration before starting another.

Response Mode

• Full migration request: inspect the project, make the edits, build, and run tests. Do not stop after giving a plan.
• Focused compile error or API question: inspect the relevant code and apply only that mapping. Do not narrate the entire workflow.
• Unsupported target framework: stop before changing packages. MSTest v4 requires .NET 8+ or .NET Framework 4.6.2+ for test applications; offer a separately approved TFM upgrade or MSTest v3 as the intermediate target.

For detailed mappings and examples, search references/mapping-cheatsheet.md for constructs actually present in the project and read only the matching sections. Do not load or reproduce the whole reference.