Platform detection

Skill dotnet/skills/plugins/dotnet-test/skills/platform-detection

Repository for skills to assist AI coding agents with .NET and C#

Install

npx -y skills add dotnet/skills --skill platform-detection

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What its author says it does

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Reference data for detecting the test platform (VSTest vs Microsoft.Testing.Platform) and test framework (MSTest, xUnit, NUnit, TUnit) from project files. DO NOT USE directly — loaded by run-tests, mtp-hot-reload, and migrate-vstest-to-mtp when they need detection logic.

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SKILL.md

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Test Platform and Framework Detection

Determine which test platform (VSTest or Microsoft.Testing.Platform) and which test framework (MSTest, xUnit, NUnit, TUnit) a project uses.

Detection files to always check (in order): global.json → .csproj → Directory.Build.props → Directory.Packages.props

Detecting the test framework

Read the .csproj file and Directory.Build.props / Directory.Packages.props (for centrally managed dependencies) and look for:

Package or SDK reference	Framework
`MSTest` (metapackage, recommended) or `<Sdk Name="MSTest.Sdk">`	MSTest
`MSTest.TestFramework` + `MSTest.TestAdapter`	MSTest (also valid for v3/v4)
`xunit`, `xunit.v3`, `xunit.v3.mtp-v1`, `xunit.v3.mtp-v2`, `xunit.v3.core.mtp-v1`, `xunit.v3.core.mtp-v2`	xUnit
`NUnit` + `NUnit3TestAdapter`	NUnit
`TUnit`	TUnit (MTP only)

Detecting the test platform

The detection logic depends on the .NET SDK version. Run dotnet --version to determine it.

.NET SDK 10+

On .NET 10+, the global.json test.runner setting is the authoritative source:

If global.json contains "test": { "runner": "Microsoft.Testing.Platform" } → MTP
If global.json has "runner": "VSTest", or no test section exists → VSTest

Important: On .NET 10+, <TestingPlatformDotnetTestSupport> alone does not switch to MTP. The global.json runner setting takes precedence. If the runner is VSTest (or unset), the project uses VSTest regardless of TestingPlatformDotnetTestSupport.

.NET SDK 8 or 9

On older SDKs, check these signals in priority order:

1. Check the <TestingPlatformDotnetTestSupport> MSBuild property. Look in the .csproj, Directory.Build.props, and Directory.Packages.props. If set to true in any of these files, the project uses MTP.

Critical: Always read Directory.Build.props and Directory.Packages.props if they exist. MTP properties are frequently set there instead of in the .csproj, so checking only the project file will miss them.

2. Check project-level signals:

Signal	Platform
`<Sdk Name="MSTest.Sdk">` as project SDK	MTP by default
`<UseMicrosoftTestingPlatformRunner>true</UseMicrosoftTestingPlatformRunner>`	MTP runner (xUnit)
`<EnableMSTestRunner>true</EnableMSTestRunner>`	MTP runner (MSTest)
`<EnableNUnitRunner>true</EnableNUnitRunner>`	MTP runner (NUnit)
`Microsoft.Testing.Platform` package referenced directly	MTP
`TUnit` package referenced	MTP (TUnit is MTP-only)

Note: The presence of Microsoft.NET.Test.Sdk does not necessarily mean VSTest. Some frameworks (e.g., MSTest) pull it in transitively for compatibility, even when MTP is enabled. Do not use this package as a signal on its own — always check the MTP signals above first. Key distinction: VSTest is the classic platform that uses vstest.console under the hood. Microsoft.Testing.Platform (MTP) is the newer, faster platform. Both can be invoked via dotnet test, but their filter syntax and CLI options differ.