Conditions

RunIf and SkipIf accept the same four conditions. Each one has a default value that leaves it out of the decision, so an attribute only tests the conditions you set.

Set them with the constructor parameters or the properties of the attribute:

• RunIf(TestOperatingSystems), RunIf(TestGlobalizationMode), RunIf(WindowsGroups) and RunIf(TestOperatingSystems, TestGlobalizationMode), and the same constructors for SkipIf;
• the OperatingSystem, GlobalizationMode, ContinuousIntegration and WindowsGroup properties, for instance [SkipIf(ContinuousIntegration = ContinuousIntegrationEnvironments.GitHubActions)].

An attribute that sets no condition has no effect: the test runs.

Operating system

TestOperatingSystems is a flags enumeration. The condition matches when the test runs on one of the listed systems: RunIf(TestOperatingSystems.Windows | TestOperatingSystems.MacOS) runs on Windows and macOS, and skips the test on Linux. On any other operating system, the condition does not match.

Globalization mode

In invariant globalization mode, .NET does not use the culture data of the operating system: culture-sensitive operations behave as if only the invariant culture existed. The mode is enabled by the InvariantGlobalization MSBuild property, or by the DOTNET_SYSTEM_GLOBALIZATION_INVARIANT environment variable.

• TestGlobalizationMode.NotInvariant matches when the culture data is available. Use it with RunIf for a test that formats or compares text with a named culture.
• TestGlobalizationMode.Invariant matches in invariant mode.

The mode is resolved like the runtime does: the System.Globalization.Invariant switch, set by the MSBuild property, takes precedence over the environment variable.

Continuous integration

ContinuousIntegrationEnvironments.GitHubActions matches when the GITHUB_ACTIONS environment variable has a non-empty value, which GitHub Actions sets on its runners. Use it with SkipIf for a test that needs something the runner lacks, or with RunIf for a test that only makes sense there.

Windows user

WindowsGroups tests the group membership of the current Windows user. Any value other than Any also requires Windows: on Linux and macOS, the condition does not match.

• WindowsGroups.Administrator matches when the process runs elevated as a member of the built-in Administrators group.
• WindowsGroups.User matches when the user is a member of the built-in Users group and the process is not elevated. Administrators are members of Users too, so an elevated process does not match.

So RunIf(WindowsGroups.Administrator) runs the test on Windows, in an elevated process only, and SkipIf(WindowsGroups.Administrator) runs it everywhere except in an elevated process on Windows.

Test the environment from code

TestEnvironment exposes the checks the attributes use, for code that adapts to the environment instead of skipping the test:

• TestEnvironment.IsGlobalizationInvariant()
• TestEnvironment.IsOnGitHubActions()
• TestEnvironment.IsOnContinuousIntegration(ContinuousIntegrationEnvironments)

public sealed class ImportTests
{
    [Fact]
    public async Task Imports_the_file_within_the_timeout()
    {
        // Shared CI runners are slower than a developer machine
        var timeout = TestEnvironment.IsOnGitHubActions() ? TimeSpan.FromMinutes(2) : TimeSpan.FromSeconds(30);
        using var cancellationTokenSource = new CancellationTokenSource(timeout);

        await File.WriteAllTextAsync(Path.GetTempFileName(), "content", cancellationTokenSource.Token);
    }
}