MSTEST0021: Prefer Dispose over TestCleanup methods

Cause

This rule raises a diagnostic when there is a void [TestCleanup] method or on any [TestCleanup] if the targeted framework supports IAsyncDisposable interface.

Rule description

To express that a test-class instance owns resources, use the standard .NET IDisposable or IAsyncDisposable pattern. MSTest invokes the disposal methods as part of per-test cleanup, so resource release can follow the same pattern as the rest of your code.

[TestCleanup] is also supported. This rule expresses an opt-in convention, not a requirement for correct test execution. MSTEST0022 offers the opposite convention; choose the cleanup policy that fits your project rather than enabling both.

How to fix violations

Replace [TestCleanup] method by Dispose or DisposeAsync pattern.

When to suppress warnings

You usually don't want to suppress warnings from this rule if you decided to opt-in for it.

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 MSTEST0021
// The code that's violating the rule is on this line.
#pragma warning restore MSTEST0021

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

[*.{cs,vb}]
dotnet_diagnostic.MSTEST0021.severity = none

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