SKILL.md
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.jsoncontains"test": { "runner": "Microsoft.Testing.Platform" }→ MTP - If
global.jsonhas"runner": "VSTest", or notestsection exists → VSTest
Important: On .NET 10+,
<TestingPlatformDotnetTestSupport>alone does not switch to MTP. Theglobal.jsonrunner setting takes precedence. If the runner is VSTest (or unset), the project uses VSTest regardless ofTestingPlatformDotnetTestSupport.
.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.propsandDirectory.Packages.propsif 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.Sdkdoes 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 usesvstest.consoleunder the hood. Microsoft.Testing.Platform (MTP) is the newer, faster platform. Both can be invoked viadotnet test, but their filter syntax and CLI options differ.