itestsessionlifetimehandler.md

The ITestSessionLifeTimeHandler

The ITestSessionLifeTimeHandler is an in-process extension that enables the execution of code before and after the test session.

To register a custom ITestSessionLifeTimeHandler, utilize the following API:

ITestApplicationBuilder testApplicationBuilder = await TestApplication.CreateBuilderAsync(args);
...
testApplicationBuilder.TestHost.AddTestSessionLifetimeHandle(serviceProvider => new CustomTestSessionLifeTimeHandler());
...

The factory utilizes the IServiceProvider to gain access to the suite of services offered by the testing platform.

Important

The sequence of registration is significant, as the APIs are called in the order they were registered.

The ITestSessionLifeTimeHandler interface includes the following methods:

public interface ITestSessionLifetimeHandler : ITestHostExtension
{
    Task OnTestSessionStartingAsync(SessionUid sessionUid, CancellationToken cancellationToken);
    Task OnTestSessionFinishingAsync(SessionUid sessionUid, CancellationToken cancellationToken);
}

public readonly struct SessionUid(string value)
{
    public string Value { get; }
}

public interface ITestHostExtension : IExtension
{
}

The ITestSessionLifetimeHandler is a type of ITestHostExtension, which serves as a base for all test host extensions. Like all other extension points, it also inherits from IExtension. Therefore, like any other extension, you can choose to enable or disable it using the IExtension.IsEnabledAsync API.

Let's describe the api:

OnTestSessionStartingAsync: This method is invoked prior to the commencement of the test session and receives the SessionUid object, which provides an opaque identifier for the current test session.

OnTestSessionFinishingAsync: This method is invoked after the completion of the test session, ensuring that the testing framework has finished executing all tests and has reported all relevant data to the platform. Typically, in this method, the extension employs the IMessageBus to transmit custom assets or data to the shared platform bus. This method can also signal to any custom out-of-process extension that the test session has concluded.

Finally, both APIs take a CancellationToken which the extension is expected to honor.

If your extension requires intensive initialization and you need to use the async/await pattern, you can refer to the Async extension initialization and cleanup. If you need to share state between extension points, you can refer to the CompositeExtensionFactory<T> section.