Run .NET Tests

Detect the test platform and framework, run tests, and apply filters using dotnet test .

When to Use

• User wants to run tests in a .NET project

• User needs to run a subset of tests using filters

• User needs help detecting which test platform (VSTest vs MTP) or framework is in use

• User wants to understand the correct filter syntax for their setup

When Not to Use

• User needs to write or generate test code (use writing-mstest-tests for MSTest, or general coding assistance for other frameworks)

• User needs to migrate from VSTest to MTP (use migrate-vstest-to-mtp )

• User wants to iterate on failing tests without rebuilding (use mtp-hot-reload )

• User needs CI/CD pipeline configuration (use CI-specific skills)

• User needs to debug a test (use debugging skills)

Inputs

Input Required Description

Project or solution path No Path to the test project (.csproj) or solution (.sln). Defaults to current directory.

Filter expression No Filter expression to select specific tests

Target framework No Target framework moniker to run against (e.g., net8.0 )

Critical Rules — Avoid Cross-Platform Mistakes

These are the most common agent mistakes. Internalize before proceeding:

Rule Why

Do NOT use --logger trx for MTP projects MTP uses --report-trx (requires the TrxReport extension package)

Do NOT use --report-trx for VSTest projects VSTest uses --logger trx

Do NOT use -- --arg on .NET SDK 10+ SDK 10+ passes MTP args directly: dotnet test --project . --report-trx

Do NOT omit -- on .NET SDK 8/9 with MTP SDK 8/9 requires the separator: dotnet test -- --report-trx

Do NOT use --filter "ClassName=..." with xUnit v3 on MTP xUnit v3 on MTP uses --filter-class , --filter-method , --filter-trait

Do NOT use bare positional path on SDK 10+ Use --project <path> or --solution <path> instead

Do NOT use --blame for MTP projects MTP uses --blame-crash and --blame-hang-timeout separately (each requires its extension package)

Do NOT use --collect "Code Coverage" for MTP MTP uses --coverage (requires the CodeCoverage extension package)

Workflow

Quick Reference

Platform SDK Command pattern

VSTest Any dotnet test [<path>] [--filter <expr>] [--logger trx]

MTP 8 or 9 dotnet test [<path>] -- <MTP_ARGS>

MTP 10+ dotnet test --project <path> <MTP_ARGS>

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

Step 1: Detect the test platform and framework

• Run dotnet --version in the project directory to determine the SDK version. This accounts for global.json SDK pinning.

• Read global.json — on .NET SDK 10+, "test": { "runner": "Microsoft.Testing.Platform" } is the authoritative MTP signal. If present, the project uses MTP and SDK 10+ syntax (no -- separator).

• Read .csproj , Directory.Build.props , and Directory.Packages.props for framework packages and MTP properties. Always check all three files — MTP properties are frequently set in Directory.Build.props rather than individual .csproj files.

• For full detection logic (SDK 8/9 signals, framework identification), see the platform-detection skill.

What to look for in each file:

File Look for Indicates

global.json

"test": { "runner": "Microsoft.Testing.Platform" }

MTP on SDK 10+

global.json

"sdk": { "version": "..." }

SDK version (determines -- separator behavior)

.csproj

<TestingPlatformDotnetTestSupport>true

MTP on SDK 8/9

.csproj

MSTest , xunit.v3 , NUnit , TUnit packages Framework identity

.csproj

Microsoft.NET.Test.Sdk

• test adapter VSTest (unless overridden by MTP signals above)

.csproj

<TargetFrameworks> (plural) Multi-TFM — may need --framework

Directory.Build.props

<TestingPlatformDotnetTestSupport>true

MTP on SDK 8/9 (often set here, not in .csproj)

Directory.Packages.props

Centrally managed test package versions Framework identity for CPM repos

Quick detection summary:

Signal Means

global.json has "test": { "runner": "Microsoft.Testing.Platform" }

MTP on SDK 10+ — pass args directly, no --

<TestingPlatformDotnetTestSupport>true in csproj or Directory.Build.props MTP on SDK 8/9 — pass args after --

Neither signal present VSTest

Step 2: Run tests

VSTest (any .NET SDK version)

dotnet test [<PROJECT> | <SOLUTION> | <DIRECTORY> | <DLL> | <EXE>]

Common flags:

Flag Description

--framework <TFM>

Target a specific framework in multi-TFM projects (e.g., net8.0 )

--no-build

Skip build, use previously built output

--filter <EXPRESSION>

Run selected tests (see Step 3)

--logger trx

Generate TRX results file

--collect "Code Coverage"

Collect code coverage using Microsoft Code Coverage (built-in, always available)

--blame

Enable blame mode to detect tests that crash the host

--blame-crash

Collect a crash dump when the test host crashes

--blame-hang-timeout <duration>

Abort test if it hangs longer than duration (e.g., 5min )

-v <level>

Verbosity: quiet , minimal , normal , detailed , diagnostic

MTP with .NET SDK 8 or 9

With <TestingPlatformDotnetTestSupport>true</TestingPlatformDotnetTestSupport> , dotnet test bridges to MTP but uses VSTest-style argument parsing. MTP-specific arguments must be passed after -- :

dotnet test [<PROJECT> | <SOLUTION> | <DIRECTORY> | <DLL> | <EXE>] -- <MTP_ARGUMENTS>

MTP with .NET SDK 10+

With the global.json runner set to Microsoft.Testing.Platform , dotnet test natively understands MTP arguments without -- :

dotnet test [--project <PROJECT_OR_DIRECTORY>] [--solution <SOLUTION_OR_DIRECTORY>] [--test-modules <EXPRESSION>] [<MTP_ARGUMENTS>]

Examples:

Run all tests in a project

dotnet test --project path/to/MyTests.csproj

Run all tests in a directory containing a project

dotnet test --project path/to/

Run all tests in a solution (sln, slnf, slnx)

dotnet test --solution path/to/MySolution.sln

Run all tests in a directory containing a solution

dotnet test --solution path/to/

Run with MTP flags

dotnet test --project path/to/MyTests.csproj --report-trx --blame-hang-timeout 5min

Note: The .NET 10+ dotnet test syntax does not accept a bare positional argument like the VSTest syntax. Use --project , --solution , or --test-modules to specify the target.

Common MTP flags

These flags apply to MTP on both SDK versions. On SDK 8/9, pass after -- ; on SDK 10+, pass directly.

Built-in flags (always available):

Flag Description

--no-build

Skip build, use previously built output

--framework <TFM>

Target a specific framework in multi-TFM projects

--results-directory <DIR>

Directory for test result output

--diagnostic

Enable diagnostic logging for the test platform

--diagnostic-output-directory <DIR>

Directory for diagnostic log output

Extension-dependent flags (require the corresponding extension package to be registered):

Flag Requires Description

--filter <EXPRESSION>

Framework-specific (not all frameworks support this) Run selected tests (see Step 3)

--report-trx

Microsoft.Testing.Extensions.TrxReport

Generate TRX results file

--report-trx-filename <FILE>

Microsoft.Testing.Extensions.TrxReport

Set TRX output filename

--blame-hang-timeout <duration>

Microsoft.Testing.Extensions.HangDump

Abort test if it hangs longer than duration (e.g., 5min )

--blame-crash

Microsoft.Testing.Extensions.CrashDump

Collect a crash dump when the test host crashes

--coverage

Microsoft.Testing.Extensions.CodeCoverage

Collect code coverage using Microsoft Code Coverage

Some frameworks (e.g., MSTest) bundle common extensions by default. Others may require explicit package references. If a flag is not recognized, check that the corresponding extension package is referenced in the project.

Alternative MTP invocations

MTP test projects are standalone executables. Beyond dotnet test , they can be run directly:

Build and run

dotnet run --project <PROJECT_PATH>

Run a previously built DLL

dotnet exec <PATH_TO_DLL>

Run the executable directly (Windows)

<PATH_TO_EXE>

These alternative invocations accept MTP command line arguments directly (no -- separator needed).

Step 3: Run filtered tests

See the filter-syntax skill for the complete filter syntax for each platform and framework combination. Key points:

• VSTest (MSTest, xUnit v2, NUnit): dotnet test --filter <EXPRESSION> with = , != , ~ , !~ operators

• MTP -- MSTest and NUnit: Same --filter syntax as VSTest; pass after -- on SDK 8/9, directly on SDK 10+

• MTP -- xUnit v3: Uses --filter-class , --filter-method , --filter-trait (not VSTest expression syntax)

• MTP -- TUnit: Uses --treenode-filter with path-based syntax

Validation

• Test platform (VSTest or MTP) was correctly identified

• Test framework (MSTest, xUnit, NUnit, TUnit) was correctly identified

• Correct dotnet test invocation was used for the detected platform and SDK version

• Filter expressions used the syntax appropriate for the platform and framework

• Test results were clearly reported to the user

Common Pitfalls

Pitfall Solution

Missing Microsoft.NET.Test.Sdk in a VSTest project Tests won't be discovered. Add <PackageReference Include="Microsoft.NET.Test.Sdk" />

Using VSTest --filter syntax with xUnit v3 on MTP xUnit v3 on MTP uses --filter-class , --filter-method , etc. -- not the VSTest expression syntax

Passing MTP args without -- on .NET SDK 8/9 Before .NET 10, MTP args must go after -- : dotnet test -- --report-trx

Using -- --arg separator on .NET SDK 10+ SDK 10+ passes MTP args directly — do NOT use -- separator

Using --logger trx for MTP or --report-trx for VSTest Each platform has its own TRX flag — check the Critical Rules table

Only checking .csproj for MTP signals Always check Directory.Build.props and Directory.Packages.props too — MTP properties are frequently set there

Using bare positional path argument on SDK 10+ SDK 10+ requires named flags: --project <path> or --solution <path>

Troubleshooting

Common error messages and how to resolve them:

Error Cause Fix

No test is available or No test matches the given testcase filter

Wrong filter syntax for the platform/framework, or tests not discovered Verify filter syntax matches the platform (see filter-syntax skill). For discovery issues, check that the test SDK and adapter packages are installed

The --report-trx option is unrecognized

MTP extension package not referenced, or using MTP flag on a VSTest project Add <PackageReference Include="Microsoft.Testing.Extensions.TrxReport" /> for MTP, or use --logger trx for VSTest

The --blame-hang-timeout option is unrecognized

Missing HangDump extension on MTP Add <PackageReference Include="Microsoft.Testing.Extensions.HangDump" />

error NETSDK1045: The current .NET SDK does not support targeting .NET X.0

SDK version in global.json doesn't match the project's target framework Update global.json SDK version or install the required SDK

The test runner process exited with non-zero exit code

MTP test host crashed or test failure Run with --blame-crash (MTP) or --blame (VSTest) to collect a crash dump for diagnosis

No test source files were found / No test project found

dotnet test can't find a test project in the given path Specify the path explicitly: dotnet test <path/to/project.csproj> (VSTest) or dotnet test --project <path> (SDK 10+)

Tests discovered but 0 executed Filter expression matches no tests Double-check filter property names and values. Common typo: TestCategory (MSTest) vs Category (NUnit) vs trait syntax (xUnit)

Using -- for MTP args on .NET SDK 10+ On .NET 10+, MTP args are passed directly: dotnet test --project . --blame-hang-timeout 5min — do NOT use -- --blame-hang-timeout

Multi-TFM project runs tests for all frameworks Use --framework <TFM> to target a specific framework

global.json runner setting ignored Requires .NET 10+ SDK. On older SDKs, use <TestingPlatformDotnetTestSupport> MSBuild property instead

TUnit --treenode-filter not recognized TUnit is MTP-only. On .NET SDK 10+ use dotnet test ; on older SDKs use dotnet run since VSTest-mode dotnet test does not support TUnit