run-tests

name

run-tests

description

Runs .NET tests with dotnet test. Use when user says "run tests", "execute tests", "dotnet test", "test filter", "filter by category", "filter by class", "run only specific tests", "tests not running", or needs to detect the test platform (VSTest or Microsoft.Testing.Platform), identify the test framework, apply test filters, or troubleshoot test execution failures. Covers MSTest, xUnit, NUnit, and TUnit across both VSTest and MTP platforms. Also use for treenode-filter, --filter-class, --filter-trait, and other framework-specific filter syntax. DO NOT USE FOR: writing or generating test code, CI/CD pipeline configuration, or debugging failing test logic.

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)

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

1. Run dotnet --version to determine the .NET SDK version
2. Read global.json, .csproj, Directory.Build.props, and Directory.Packages.props
3. Follow the detection procedure in references/platform-detection.md to determine:
   • Test framework: MSTest, xUnit, NUnit, or TUnit
   • Test platform: VSTest or Microsoft.Testing.Platform (MTP)

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 references/filter-syntax.md 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 -- for MTP args on .NET SDK 10+	On .NET 10+, MTP args are passed directly: dotnet test --report-trx (using -- still works but is unnecessary)
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