run-tests

name	run-tests
description	Run .NET tests or give the exact repository-compatible command. Use for "run the tests", one test/class/category/trait, one target framework, "what dotnet test command?", `--no-build`, `--diag`, diagnostic logs, classic packages.config or MSTest.exe, TRX or coverage collection, crash/hang dumps, filter mismatch, `--filter-query`, a single combined filter expression, or unrecognized options. Handles VSTest and bridged/native Microsoft.Testing.Platform across MSTest/xUnit/NUnit/TUnit, including NUnit bridge filters, xUnit v3 class/trait/query filters, multi-TFM, and argument order. For identification-only requests, use platform-detection. DO NOT USE for writing tests, hot-reload/no-rebuild loops, migration, CI, coverage analysis, or debugging test logic.
license	MIT

Run .NET Tests

Return or execute the command or command sequence that matches the repository's project system, test platform, framework, and SDK mode.

Scope and tool policy

Choose the smallest path that satisfies the request:

Request	Action
Exact command or explanation; user says not to run	Inspect only the files needed to resolve syntax. Do not restore, build, or run tests.
Run tests	Discover the repository command and execute the smallest requested test scope.
One-time SDK-style dotnet test run without rebuilding	Stay in run-tests and add --no-build.
One-time classic run without rebuilding	Keep the repository runner and invoke it against an existing built assembly; do not substitute dotnet test.
Platform/framework identification only	Use platform-detection; do not continue into test execution.
Explicit hot reload or a keep-running edit/re-run loop	Use mtp-hot-reload.
Filter needed and the framework-specific syntax is not already clear	Load filter-syntax; do not load it for unfiltered runs.

Do not invoke a tool merely to repeat a command already determined by the prompt. Do not build first "just in case": dotnet test builds by default. Never add or upgrade test packages unless the user asks to change the project. For an exact-command request, return one runnable command first. Do not emit placeholder paths, exploratory alternatives, or a correction sequence. Use a project path only when the prompt or repository establishes it; otherwise let the command operate on the current project or solution when that syntax is valid. Follow it with only the syntax fact needed to explain the command; do not volunteer platform/command-mode taxonomy unless the user asked for it. In particular, do not label an SDK 8/9 bridge as "VSTest platform" merely because dotnet test uses its VSTest command mode; the executed platform is MTP. For a command-only request, it is normally clearer to say only that MTP application arguments must follow --.

Inputs to discover

• Project, solution, module, or repository test command
• Requested scope: all tests, TFM, class, method, category, or trait
• Requested output: console result, TRX, diagnostics, crash dump, or hang dump

When those facts are present in the prompt, use them. Otherwise inspect only the relevant files: global.json, the selected project, packages.config, Directory.Build.props, Directory.Packages.props, then repository scripts/CI documentation. For a file-backed request, enumerate those configuration names once and read all relevant files that are present in one batch; never infer that a runner or bridge property is absent merely because it is not in the .csproj. Load platform-detection only when those signals need precedence analysis; do not duplicate its full analysis in the response. If execution is requested and the command depends on the active SDK but neither the prompt nor global.json establishes it, run dotnet --version once. For a command-only request that prohibits execution, do not probe: state the required SDK assumption or ask for the SDK version when the syntax cannot otherwise be resolved. Route identification-only requests to platform-detection.

Decision table

Detected mode / platform	Command shape	Never use
Classic non-SDK	Repository script, or full MSBuild followed by vstest.console.exe / MSTest.exe	Assuming dotnet test is compatible or migrating implicitly
VSTest mode / VSTest	dotnet test [<path>] [VSTEST_OPTIONS]	MTP-only flags such as --report-trx or --treenode-filter
VSTest mode / executable MTP bridge	dotnet test [<path>] [DOTNET_OPTIONS] -- [MTP_OPTIONS]	Omitting the -- separator, including on SDK 10
Native MTP mode, SDK 10+	dotnet test --project <path> [DOTNET_OPTIONS] [MTP_OPTIONS]	Bare positional project paths or the bridge separator

global.json controls the dotnet test command mode on SDK 10+, not necessarily the platform that executes tests. A VSTest-mode project with an MTP runner, TestingPlatformDotnetTestSupport=true, and final OutputType=Exe is still bridge syntax with --. SDK 8/9 only has VSTest command mode.

--project is valid only in SDK 10+ native MTP command mode (selected by global.json test.runner). Never use it for VSTest mode or an SDK 8/9 bridge; those forms take a positional project path. Conversely, native MTP options are direct arguments and must not be placed after a bridge separator.

Keep dotnet test/MSBuild options such as --framework, --configuration, --no-build, and --verbosity before --. Put only MTP application arguments after -- in bridge mode.

Workflow

1. Resolve the repository-compatible runner.

For classic projects, signals include ToolsVersion, explicit Compile and Reference items, legacy imports, and packages.config. Prefer a checked-in script or documented CI command. A typical fallback is:

nuget restore MySolution.sln
MSBuild.exe MySolution.sln /t:Build /p:Configuration=Debug
vstest.console.exe path\to\MyTests.dll /TestAdapterPath:path\to\adapter\build\<tfm>

For packages.config, restore with NuGet before the build unless the imported package files are already present. If adapter discovery is not repository- configured, derive /TestAdapterPath from the restored adapter package path or the adapter .props/.targets imports; do not guess the package root.

For a requested no-rebuild run, omit the build step and invoke the repository's test runner only when the expected assembly already exists. Otherwise report the missing build output rather than silently rebuilding or switching runners.

For a requested subset, keep the repository runner and use its filter syntax: vstest.console.exe path\to\MyTests.dll /TestCaseFilter:"TestCategory=Integration". Older MSTest.exe repositories may use /test:<name> or /category:<category> instead. Do not substitute the later dotnet test filter examples for a classic runner.

Use the installed adapter-compatible VSTest/MSTest toolchain. If it is not available, state the missing prerequisite and the documented command; do not claim tests ran.

For SDK-style projects, distinguish:

Signal	Meaning
SDK 10+ global.json selects Microsoft.Testing.Platform	Native MTP command mode
VSTest mode + enabled MTP runner + final TestingPlatformDotnetTestSupport=true + final OutputType=Exe	Executable VSTest-to-MTP bridge
VSTest mode without a complete runner-and-bridge combination	VSTest
Microsoft.NET.Test.Sdk plus adapter, without stronger MTP signals	VSTest
TUnit	MTP-only; use a configured bridge/native mode or the test executable

Evaluate properties from the project and imported Directory.Build.props/Directory.Packages.props. Respect project-level overrides and per-target-framework conditions. A runner and bridge without an executable final output are an incomplete MTP configuration, not a usable bridge.

2. Select the command and requested scope.

# VSTest mode
dotnet test path/to/Tests.csproj

# VSTest mode that bridges to MTP
dotnet test path/to/Tests.csproj -- <MTP_OPTIONS>

# Native MTP mode on SDK 10+
dotnet test --project path/to/Tests.csproj <MTP_OPTIONS>

# One target framework; this stays before the bridge separator
dotnet test path/to/Tests.csproj --framework net9.0 -- <MTP_OPTIONS>

For native MTP, use --project, --solution, or --test-modules; positional paths belong to VSTest mode.

If the user names a subset, do not run the whole suite. Inspect test attributes only when needed to translate a human label such as "integration" or "smoke" into the framework's actual category/trait name.

When a VSTest class filter must distinguish similarly named classes, combine the positive selector with an explicit negative selector rather than relying on an incidental substring difference.

3. Apply platform- and framework-correct filters.

Load filter-syntax only when the request is filtered and the framework-specific syntax is not already clear. The common decisions are:

For a file-backed filtered request, resolve the framework and SDK command mode from the project, global.json, and imported props before choosing syntax. Do not infer VSTest syntax merely from Microsoft.NET.Test.Sdk or from the framework name.

Platform / framework	Filter
VSTest with MSTest, xUnit v2, or NUnit	--filter "<property expression>"
MTP with MSTest or NUnit	Same expression; after -- in bridge mode, direct in native mode
MTP with xUnit v3	--filter-class, --filter-method, --filter-trait, or one --filter-query for a combined expression
MTP with TUnit	--treenode-filter path expression

Examples:

# VSTest MSTest/NUnit
dotnet test --filter "FullyQualifiedName~OrderServiceTests&TestCategory=Unit"

# SDK 8/9 or SDK 10 VSTest-mode MTP bridge, xUnit v3
dotnet test -- --filter-trait "Category=Integration"

# Native MTP, xUnit v3
dotnet test --project Tests.csproj --filter-class "*ShoppingCartTests*"

# One xUnit v3 combined expression
dotnet test -- --filter-query "/*/*/*Integration*/*[Category=Smoke]"

# TUnit on SDK 8/9 with a configured VSTest-to-MTP bridge
dotnet test -- --treenode-filter "/*/*/SmsNotificationTests/*"

# TUnit executable fallback when no bridge is configured
dotnet run --project Tests.csproj -- --treenode-filter "/*/*/SmsNotificationTests/*"

Do not use VSTest --filter "ClassName=..." with xUnit v3 on MTP. Do not use a generic VSTest expression with TUnit. When the user requests one combined xUnit query expression, return only one --filter-query command; do not replace it with separate filter flags or offer speculative alternative grammars.

4. Add reports or diagnostics.

Outcome	VSTest	MTP
TRX	SDK-style: --logger "trx;LogFileName=<name>.trx" when an exact output file is requested, otherwise --logger trx; standalone vstest.console.exe: /Logger:trx; MSTest.exe: repository-documented results option	--report-trx
Results directory	--results-directory <dir>	--results-directory <dir>
Diagnostic log	--diag <file>	--diagnostic --diagnostic-output-directory <dir>
Crash dump	--blame-crash	--crashdump
Hang timeout	--blame-hang --blame-hang-timeout 5min	--hangdump --hangdump-timeout 5min
Code coverage	--collect "Code Coverage"	--coverage

MTP report, dump, and coverage flags require their corresponding registered extensions (TrxReport, CrashDump, HangDump, or CodeCoverage). Some framework SDKs bundle common extensions; if a flag is unrecognized, inspect package references before recommending a package change.

--verbosity diagnostic increases dotnet/MSBuild output verbosity; it does not write a VSTest diagnostic log file.

Examples:

# VSTest TRX
dotnet test Tests.csproj --logger "trx;LogFileName=TestResults.trx"

# MTP bridge TRX
dotnet test Tests.csproj -- --report-trx

# Native MTP TRX and hang detection
dotnet test --project Tests.csproj --report-trx --hangdump --hangdump-timeout 5min

5. Execute only when requested.

Run the narrowest command or sequence that answers the request. Capture each command, exit code, and test summary. A failed restore/build is not a test failure, and a test failure is not a tool failure. Report which phase failed and include the actionable diagnostic. Never claim a clean run unless the sequence completed successfully with the intended tests executed. For a filtered run, a successful exit is not enough: confirm the reported test names or count match the requested scope. If the filter was ignored, correct the platform-specific syntax and rerun before reporting success.

Output contract

• Command-only request: lead with the exact command or command sequence, then one short syntax explanation.
• Execution request: report the exact command or command sequence and a literal Passed: N, Failed: N, Skipped: N summary from the completed run; include the first actionable failure.
• Detection needed only to choose syntax: state the selected mode/platform briefly, not a separate detection report.
• Missing prerequisite or incompatible configuration: name it explicitly and stop rather than returning a success-shaped fallback.

Validation

• The command matches classic, VSTest, bridged MTP, or native MTP mode.
• The framework-specific filter targets the requested subset.
• --framework and other dotnet test options are before any bridge separator.
• SDK 8/9 bridge commands contain --; --project appears only in SDK 10+ native MTP mode.
• TRX, diagnostics, dump, and coverage flags match the platform.
• No restore, build, or test was run for an advisory-only request.
• Reported results match the actual command outcome.