Masstransit v8 test consumer with TestServer

Question

I try to test MassTransit v8 consumer with TestServer by creating whole application with all DI services. I have created TestServer instance with replaced some dependencies but I am most concerned with adding MasstransitTestHarness with consumer. In test message is sent and consumed by harness correctly, but I can't understand why my consumer can't consume message. TestStartup inherits from my application Startup when I have defined all DI services.

Here is an example of my code:

TestServer program

public class TestProgram
{
    private const string API_URL = "http://localhost:5010";

    public TestServer Server { get; set; }

    public void SetUpTestServer()
    {
        var host = CreateWebHostBuilder();

        Server = new TestServer(host);
    }

    private IWebHostBuilder CreateWebHostBuilder()
    {
        return new WebHostBuilder()
            .ConfigureTestServices(serviceCollection =>
            {
                serviceCollection.AddMassTransitTestHarness(cfg =>
                {
                    cfg.AddConsumer<MyConsumer>();

                    cfg.UsingInMemory((provider, config) =>
                    {
                        config.ReceiveEndpoint("MyMessageQueue",
                            e =>
                            {
                                e.Batch<IMyMessage>(b =>
                                {
                                    b.Consumer<MyConsumer, IMyMessage>(provider);
                                });
                            });
                    });
                });
            })
            .UseStartup<TestStartup>()
            .UseUrls(API_URL)
            .UseEnvironment("Test");
    }
}

Single test

public async Task Test()
{
    EndpointConvention.Map<IMyMessage>(new Uri($"queue:MyMessageQueue"));

    var program = new TestProgram();
    program.SetUpTestServer();

    var harness = program.Server.Services.GetTestHarness();
    await harness.Start();

    try
    {
        await harness.Bus.Send<IMyMessage>(new MyMessage());

        // It's OK
        Assert.IsTrue(await harness.Sent.Any<IMyMessage>());
        Assert.IsTrue(await harness.Consumed.Any<IMyMessage>());

        var consumer = harness.GetConsumerHarness<MyConsumer>();
        // It's wrong
        Assert.That(await consumer.Consumed.Any<IMyMessage>());
    }
    finally
    {
        await harness.Stop();
    }
}

Does anyone know why my consumer not consume sent message?

Answer 1

Your configuration is strange, you should follow the configuration guide:

private IWebHostBuilder CreateWebHostBuilder()
{
    return new WebHostBuilder()
        .ConfigureTestServices(serviceCollection =>
        {
            serviceCollection.AddMassTransitTestHarness(cfg =>
            {
                cfg.AddConsumer<MyConsumer>(c =>
                    c.Options<BatchOptions>(o => o.SetMessageLimit(5).SetTimeLimit(2000)))
                    .Endpoint(e => e.Name = "MyMessageQueue");;
            });
        })
        .UseStartup<TestStartup>()
        .UseUrls(API_URL)
        .UseEnvironment("Test");
}

Also, the consumer doesn't consume IMyMessage , it consumes Batch<IMyMessage> , and I'm not entirely sure that consuming batch messages is visible in the harness, I'd have to check and be sure.

Also, as a complete test for comparison:

[TestFixture]
public class When_batch_limit_is_reached
{
    [Test]
    public async Task Should_deliver_the_batch_to_the_consumer()
    {
        await using var provider = new ServiceCollection()
            .AddMassTransitTestHarness(x =>
            {
                x.AddConsumer<TestBatchConsumer>();
            })
            .BuildServiceProvider(true);

        var harness = provider.GetTestHarness();

        await harness.Start();

        await harness.Bus.PublishBatch(new[] { new BatchItem(), new BatchItem() });

        Assert.That(await harness.Consumed.SelectAsync<BatchItem>().Take(2).Count(), Is.EqualTo(2));

        Assert.That(await harness.GetConsumerHarness<TestBatchConsumer>().Consumed.Any<Batch<BatchItem>>(), Is.True);

        Assert.That(await harness.Published.Any<BatchResult>(x => x.Context.Message.Count == 2), Is.True);
    }
}