MSTEST0054: Use cancellation token from TestContext.CancellationToken

Cause

Accessing CancellationToken via TestContext.CancellationTokenSource.Token instead of using the TestContext.CancellationToken property.

Rule description

MSTest controls cancellation of the test's execution. To let an operation observe that cancellation, pass TestContext.CancellationToken directly instead of accessing the framework's CancellationTokenSource.

A CancellationToken lets your code observe cancellation without exposing the source's cancellation and disposal operations. The direct property expresses that ownership boundary and avoids a dependency on the older source property when all you need is its token.

How to fix violations

Use the TestContext.CancellationToken property instead of TestContext.CancellationTokenSource.Token.

For example, change this:

public TestContext TestContext { get; set; }

[TestMethod]
public async Task TestMethod()
{
    await Task.Delay(1000, TestContext.CancellationTokenSource.Token);
}

To this:

public TestContext TestContext { get; set; }

[TestMethod]
public async Task TestMethod()
{
    await Task.Delay(1000, TestContext.CancellationToken);
}

When to suppress warnings

Don't suppress warnings from this rule. The use of CancellationTokenSource property is not recommended and might be removed in a future release.