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MSTEST0072: '[AssemblyFixtureProvider]' isn't supported with ahead-of-time compilation

Property Value
Rule ID MSTEST0072
Title '[AssemblyFixtureProvider]' isn't supported with ahead-of-time compilation
Category Usage
Fix is breaking or non-breaking Non-breaking
Enabled by default Yes
Default severity Warning
Introduced in version 4.4.0 (preview)
Is there a code fix No

Important

This analyzer is planned for MSTest 4.4 and is available only in preview builds until MSTest 4.4.0 is released.

Cause

A project applies [AssemblyFixtureProvider], either directly or through a referenced library, while publishing with Native AOT (PublishAot) or Blazor WebAssembly AOT (RunAOTCompilation).

Rule description

[AssemblyFixtureProvider] discovery walks the runtime assembly reference graph, which requires the runtime to generate dynamic code. Ahead-of-time compilation flavors such as Native AOT and Blazor WebAssembly AOT can't generate dynamic code, so the runtime silently skips discovery, and the fixture's [AssemblyInitialize]/[AssemblyCleanup] methods never run.

// Violation: ignored at run time under Native AOT / Blazor WebAssembly AOT.
[assembly: AssemblyFixtureProvider(typeof(SharedFixtures))]

The analyzer reports this diagnostic whether the attribute is applied in the current compilation or on a referenced assembly, because either way the consuming Native AOT test project silently loses its assembly fixtures.

How to fix violations

Declare the [AssemblyInitialize] and [AssemblyCleanup] methods directly in the test assembly instead of relying on a shared [AssemblyFixtureProvider] library.

public static class Fixtures
{
    [AssemblyInitialize]
    public static void Init(TestContext context) { }
}

When to suppress warnings

Don't suppress warnings from this rule for a project that actually publishes with Native AOT or Blazor WebAssembly AOT, because the fixture methods won't run and any state they set up won't exist for your tests. Suppressing is reasonable only if the AOT-published configuration doesn't run the affected tests.

Suppress a warning

If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable MSTEST0072
// The code that's violating the rule is on this line.
#pragma warning restore MSTEST0072

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.{cs,vb}]
dotnet_diagnostic.MSTEST0072.severity = none

For more information, see How to suppress code analysis warnings.

See also

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