Program.cs

using Microsoft.Testing.Platform.Builder;
using Microsoft.Testing.Platform.Capabilities.TestFramework;
using Microsoft.Testing.Platform.Extensions.Messages;
using Microsoft.Testing.Platform.Extensions.TestFramework;

for (int i = 0; i < 3; i++)
{
	Console.WriteLine(new string('a', 10000));
	Console.Error.WriteLine(new string('e', 10000));
}

var testApplicationBuilder = await TestApplication.CreateBuilderAsync(args);

testApplicationBuilder.RegisterTestFramework(_ => new TestFrameworkCapabilities(), (_, __) => new DummyTestAdapter());

using var testApplication = await testApplicationBuilder.BuildAsync();
return await testApplication.RunAsync();

public class DummyTestAdapter : ITestFramework, IDataProducer
{
	public string Uid => nameof(DummyTestAdapter);

	public string Version => "2.0.0";

	public string DisplayName => nameof(DummyTestAdapter);

	public string Description => nameof(DummyTestAdapter);

	public Task<bool> IsEnabledAsync() => Task.FromResult(true);

	public Type[] DataTypesProduced => new[] {
		typeof(TestNodeUpdateMessage)
	};

	public Task<CreateTestSessionResult> CreateTestSessionAsync(CreateTestSessionContext context)
		=> Task.FromResult(new CreateTestSessionResult() { IsSuccess = true });

	public Task<CloseTestSessionResult> CloseTestSessionAsync(CloseTestSessionContext context)
		=> Task.FromResult(new CloseTestSessionResult() { IsSuccess = true });

	public async Task ExecuteRequestAsync(ExecuteRequestContext context)
	{	
		await context.MessageBus.PublishAsync(this, new TestNodeUpdateMessage(context.Request.Session.SessionUid, new TestNode()
		{
			Uid = "Test0",
			DisplayName = "Test0",
			Properties = new PropertyBag(new PassedTestNodeStateProperty("OK")),
		}));

		await context.MessageBus.PublishAsync(this, new TestNodeUpdateMessage(context.Request.Session.SessionUid, new TestNode()
		{
			Uid = "Test1",
			DisplayName = "Test1",
			Properties = new PropertyBag(new SkippedTestNodeStateProperty("OK skipped!")),
		}));
		
		await context.MessageBus.PublishAsync(this, new TestNodeUpdateMessage(context.Request.Session.SessionUid, new TestNode()
		{
			Uid = "Test2",
			DisplayName = "Test2",
			Properties = new PropertyBag(new FailedTestNodeStateProperty(new Exception("this is a failed test"), "not OK")),
		}));

		context.Complete();
	}
}