Possible to make RemoveMassTransit(...) and RemoveSagaRepositories(...) public?

[ChThy]

Hi,

Would it be possible make the following extension methods public?

• MassTransit.DependencyInjectionRegistrationExtensions.RemoveMassTransit(IServiceCollection)
• MassTransit.Configuration.RegistrationServiceCollectionExtensions.RemoveSagaRepositories(IServiceCollection)

Motivation is to make it easier to remove the MassTransit configuration in integration tests.

[lkomanetz]

Does this YouTube video help at all with setting up integration tests?
https://www.youtube.com/watch?v=Uzme7vInDz0

Also, in the MassTransit namespace there is an extension method for IServiceCollection called RemoveMassTransitHostedService(). Would that be any help?

[ChThy]

No not really. I looked into using the TestHarness but it has some inconsitent behaviour for saga states compared to using a real database (see #5171). Adding the TestHarness to the DI container makes all saga repositories inmemory, but I only want to use the inmemory message transport.

RemoveMassTransitHostedService() is only removing the hosted service which starts the bus. All other MassTransit services stay registered. So when calling AddMasstransit() again (instead of AddMassTransitTestHarness()) in integration tests, an exception is thrown because that method was already called by the application to be tested. Therefore, if these methods are public, we could use them in integration test setup to remove MassTransit from DI, then re-add it using the inmemory transport. Filters could then be used to observe in- and outgoing messages for test assertion in combination with query'ing the database for saga state.

Looking into the code to see which services are removed and duplicate these methods is also an option. But then we would have to watch it closely for changes when new services arise.

[phatboyg]

What about AddMassTransitTestHarness isn't meeting your needs? You can literally configure anything that can be configured using AddMassTransit but with all the test harness support.

[ChThy]

The SagaTestHarness doesn't seem to play nice with another persistence configured. Below some code snippets which adds the TestHarness and configures a SagaStateMachine with EF Core SQL Server persistence. When throwing an exception in the saga during Initial state, a Fault<> event is published. This is then also consumed by the same saga. Only the last one has to create a saga instance in a FaultedState. When testing this using the TestHarness, the Sagas property contains 2 instance instead of 1.

What is the recommended approach to test tis situation?

SagaStateMachine:

public class ReceptionSaga : MassTransitStateMachine<ReceptionState>
{
    public ReceptionSaga()
    {
        InstanceState(e => e.CurrentState);
        CorrelateEvents();
        
        Initially(
            When(PackageRegistered)
                .Then(ctx =>
                {
                    ctx.Saga.PackageIdentifier = ctx.Message.PackageIdentifier;
                    ctx.Saga.Sender = ctx.Message.Sender;
                    ctx.Saga.Destination = ctx.Message.Destination;
                    ctx.Saga.RegisteredOn = ctx.Message.EventTimestamp;
                    
                    if (ctx.Message.Destination.Equals("sun", StringComparison.OrdinalIgnoreCase))
                    {
                        throw new InvalidOperationException("Can't send packages to the sun");
                    }
                })
                .TransitionTo(PackageRegisteredState),
            When(PackageRegisteredFaulted)
                .Then(ctx =>
                {
                    ctx.Saga.PackageIdentifier = ctx.Message.Message.PackageIdentifier;
                    ctx.Saga.Destination = ctx.Message.Message.Destination;
                    ctx.Saga.Sender = ctx.Message.Message.Sender;
                    TransitionToFaultedState(ctx, new Error("123", "Registration faulted"));
                })
        );
        
        During(PackageRegisteredState, When(PackageReceived)
            .Then(ctx =>
            {
                if (ctx.Saga.Destination != ctx.Message.Destination)
                {
                    throw new Exception($"Destination mismatch!");
                }

                ctx.Saga.ReceivedOn = ctx.Message.ReceivedOn;
            })
            .TransitionTo(PackagedReceivedState));
        
        During(PackagedReceivedState,
            Ignore(PackageRegistered),
            Ignore(PackageReceived));

        DuringAny(
            When(PackageRegisteredFaulted).Then(ctx =>
            {
                ctx.Saga.PackageIdentifier = ctx.Message.Message.PackageIdentifier;
                TransitionToFaultedState(ctx, new Error("123", "Registration faulted"));
            }),
            When(PackageReceivedFaulted).Then(ctx =>
            {
                ctx.Saga.PackageIdentifier = ctx.Message.Message.PackageIdentifier;
                TransitionToFaultedState(ctx, new Error("456", "Reception faulted"));
            })
        );
    }

    private void TransitionToFaultedState(BehaviorContext<ReceptionState> ctx, Error error)
    {
        ctx.Saga.Errors.Add(error);
        ctx.TransitionToState(FaultedState);
    }
    
    private void CorrelateEvents()
    {
        Event(() => PackageRegistered, x
            => x.CorrelateBy(s => s.PackageIdentifier, c => c.Message.PackageIdentifier));
        Event(() => PackageReceived, x
            => x.CorrelateBy(s => s.PackageIdentifier, c => c.Message.PackageIdentifier));
        Event(() => PackageRegisteredFaulted, x
            => x.CorrelateBy(s => s.PackageIdentifier, c => c.Message.Message.PackageIdentifier));
        Event(() => PackageReceivedFaulted, x
            => x.CorrelateBy(s => s.PackageIdentifier, c => c.Message.Message.PackageIdentifier));
    }

    public Event<PackageRegistered> PackageRegistered { get; private set; } = null!;
    public Event<PackageReceived> PackageReceived { get; private set; } = null!;
    public Event<Fault<PackageRegistered>> PackageRegisteredFaulted { get; private set; } = null!;
    public Event<Fault<PackageReceived>> PackageReceivedFaulted { get; private set; } = null!;

    public State PackageRegisteredState { get; private set; } = null!;
    public State PackagedReceivedState { get; private set; } = null!;
    public State ProcessedState { get; private set; } = null!;

    public State FaultedState { get; private set; } = null!;
}

With this configuration when setting up the WebApplicationFactory:

var factory = new WebApplicationFactory<Program>()
            .WithWebHostBuilder(builder =>
            {
                builder.UseEnvironment("IntegrationTesting");
                builder.ConfigureServices(services =>
                {
                    services.Configure<TestHarnessOptions>(o =>
                    {
                        o.TestTimeout = Debugger.IsAttached ? TimeSpan.FromMinutes(50) : TestTimeOut;
                        o.TestInactivityTimeout = Debugger.IsAttached ? TimeSpan.FromMinutes(50) : TestInactivityTimeoutSeconds;
                    });
                    services.AddMassTransitTestHarness(busConfig =>
                    {
                        busConfig.AddEntityFrameworkOutbox<ApplicationDbContext>(config =>
                        {
                            config.UseSqlServer();
                        });

                        busConfig.AddSagaStateMachine<ReceptionSaga, ReceptionState>()
                            .EntityFrameworkRepository(ef =>
                            {
                                ef.ConcurrencyMode = ConcurrencyMode.Optimistic;
                                ef.ExistingDbContext<ApplicationDbContext>();
                                ef.UseSqlServer();
                            });

                        busConfig.UsingInMemory((context, config) =>
                        {
                            config.ConfigureEndpoints(context);
                        });
                    });
                });
                builder.ConfigureAppConfiguration((context, config) =>
                {
                    config.AddInMemoryCollection(new Dictionary<string, string?>
                    {
                        { "ConnectionStrings:Database", DatabaseFixture.TestDatabaseConnectionString },
                        { "ConnectionStrings:AzureServiceBus", "" }
                    });
                });
            });

Then the following assertion fails with exception: System.InvalidOperationException : Sequence contains more than one element

[Fact]
    public async Task StateShouldBeFaulted()
    {
        var registerPackageRequest = new PackageRegistered("1", "Sipley", "Sun");
        await Client.PostAsJsonAsync("packages/register", registerPackageRequest);

        var sagaTestHarness = GetSagaTestHarness();
        (await sagaTestHarness.Consumed.Any<PackageRegistered>()).ShouldBeTrue();
        (await sagaTestHarness.Consumed.Any<Fault<PackageRegistered>>()).ShouldBeTrue();
        (await sagaTestHarness.Created.Any(state => state.PackageIdentifier == "1", GetTimeoutToken(10000))).ShouldBeTrue();
        
        await AssertState(sagaTestHarness, "1", nameof(ReceptionSaga.FaultedState));
    }

Full sample attached:
MtExceptionInSagaRepro.zip