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VSTest Bridge extension

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This extension provides a compatibility layer with VSTest allowing the test frameworks depending on it to continue supporting running in VSTest mode (vstest.console.exe, usual dotnet test, VSTest task on AzDo, Test Explorers of Visual Studio and Visual Studio Code...). This extension is shipped as part of Microsoft.Testing.Extensions.VSTestBridge package.

Important

The package is shipped with Microsoft .NET library closed-source free to use licensing model.

Compatibility with VSTest

The main purpose of this extension is to offer an easy and smooth upgrade experience for VSTest users by allowing a dual mode where the new platform is enabled and in parallel a compatibility mode is offered to allow the usual workflows to continue working.

Runsettings support

This extension allows you to provide a VSTest .runsettings file, but not all options in this file are picked up by the platform. We describe below the supported and unsupported settings, configuration options and alternatives for the most used VSTest configuration options.

When enabled by the test framework, you can use --settings <SETTINGS_FILE> to provide the .runsettings file.

RunConfiguration element

The RunConfiguration element can include the following elements. None of these settings are respected by Microsoft.Testing.Platform:

Node Description Reason / Workaround
MaxCpuCount This setting controls the level of parallelism on process-level. Use 0 to enable the maximum process-level parallelism. When Microsoft.Testing.Platform is used with MSBuild, this option is offloaded to MSBuild. When a single executable is run, this option has no meaning for Microsoft.Testing.Platform.
ResultsDirectory The directory where test results are placed. The path is relative to the directory that contains the .runsettings file. Use the command-line option --results-directory to determine the directory where the test results are going to be placed. If the specified directory doesn't exist, it's created. The default is TestResults in the directory that contains the test application.
TargetFrameworkVersion This setting defines the framework version, or framework family to use to run tests. This option is ignored. The <TargetFramework> or <TargetFrameworks> MSBuild properties determine the target framework of the application. The tests are hosted in the final application.
TargetPlatform This setting defines the architecture to use to run tests. <RuntimeIdentifier> determines the architecture of the final application that hosts the tests.
TreatTestAdapterErrorsAsWarnings Suppresses test adapter errors to become warnings. Microsoft.Testing.Platform allows only one type of tests to be run from a single assembly, and failure to load the test framework or other parts of infrastructure will become an un-skippable error, because it signifies that some tests could not be discovered or run.
TestAdaptersPaths One or more paths to the directory where the TestAdapters are located Microsoft.Testing.Platform does not use the concept of test adapters and does not allow dynamic loading of extensions unless they are part of the build, and are registered in Program.cs, either automatically via build targets or manually.
TestCaseFilter A filter to limit tests which will run. To filter tests use --filter command line option.
TestSessionTimeout Allows users to terminate a test session when it exceeds a given timeout. There is no alternative option.
DotnetHostPath Specify a custom path to dotnet host that is used to run the test host. Microsoft.Testing.Platform is not doing any additional resolving of dotnet. It depends fully on how dotnet resolves itself, which can be controlled by environment variables such as DOTNET_HOST_PATH.
TreatNoTestsAsError Exit with non-zero exit code when no tests are discovered. Microsoft.Testing.Platform will error by default when no tests are discovered or run in a test application. You can set how many tests you expect to find in the assembly by using --minimum-expected-tests command line parameter, which defaults to 1.

DataCollectors element

Microsoft.Testing.Platform is not using data collectors. Instead it has the concept of in-process and out-of-process extensions. Each extension is configured by its respective configuration file or through the command line.

Most importantly hang and crash extension, and code coverage extension.

LoggerRunSettings element

Loggers in Microsoft.Testing.Platform are configured through command-line parameters or by settings in code.

VSTest filter support

This extension also offer the ability to use VSTest filtering mechanism to discover or run only the tests that matches the filter expression. For more information, see the Filter option details section or for framework specific details see the Running selective unit tests page.

When enabled by the test framework, you can use --filter <FILTER_EXPRESSION>.