Clarify MSTest.Sdk incompatibility with ASP.NET Core (Microsoft.NET.Sdk.Web)

[Copilot]

The "Enable MTP in an MSTest project" section didn't explain that MSTest.Sdk replaces Microsoft.NET.Sdk as the project SDK—making it incompatible with ASP.NET Core integration test projects that require Microsoft.NET.Sdk.Web. The "alternatively" paragraph also didn't make clear when to use manual configuration over the SDK approach.

Changes

• Rewrote intro paragraph — Direct imperative form; explicitly states that MSTest.Sdk replaces Microsoft.NET.Sdk as the project SDK with MTP enabled by default.
• Added NOTE callout — Calls out that MSTest.Sdk isn't compatible with projects requiring a different SDK, with Microsoft.NET.Sdk.Web (ASP.NET Core) as the concrete example.
• Rewrote the "alternatively" paragraph — Now clearly scoped to projects using a SDK other than Microsoft.NET.Sdk. Removed the "We strongly recommend" phrasing per style guide.

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Internal previews

📄 File	🔗 Preview link
docs/core/testing/unit-testing-mstest-running-tests.md	Run tests with MSTest

[Youssef1313]

Have we tried one of the following?

<Project Sdk="Microsoft.NET.Sdk.Web">
  <Import Project="Sdk.props" Sdk="MSTest.Sdk" />

  // ...

  <Import Project="Sdk.targets" Sdk="MSTest.Sdk" />
</Project>

or

<Project Sdk="MSTest.Sdk">
  <Import Project="Sdk.props" Sdk="Microsoft.NET.Sdk.Web" />

  // ...

  <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk.Web" />
</Project>

to see if that works? And if it does work, do we want to make that recommendation?

And if it doesn't work, is there anything that MSTest.Sdk could adjust to make that work?

[adegeo]

Hey @Youssef1313 :)

I'm really trying to just correct the issue at hand which is there is some ambiguity as to when you can actually take the prescribed course of replacing the SDK entry. If you can test and suggest a different suggestion in the article, that would be great! I did just reedit the Copilot suggestions and I think it's clearer this time. So please re-review.

[Copilot]

Pull request overview

This PR clarifies how to enable Microsoft.Testing.Platform (MTP) in MSTest projects by explaining that MSTest.Sdk replaces the project SDK, which makes it unsuitable for projects that must use a different top-level SDK (for example, Microsoft.NET.Sdk.Web for ASP.NET Core integration tests). It also tightens guidance on when to use the manual configuration approach.

Changes:

• Rewrites the “Enable MTP in an MSTest project” intro to be more direct and explicit about MSTest.Sdk replacing the project SDK.
• Adds a NOTE callout explaining why MSTest.Sdk shouldn’t be used when a project needs a different SDK (example: ASP.NET Core).
• Rewrites the “Alternatively” guidance to scope it to non-Microsoft.NET.Sdk projects and explain the manual setup path.