XUnit unit tests for MassTransit consumer

Question

I am using MassTransit 5.5.5 version and xunit 2.4.1

My consumer looks like this

public class StorageInformationConsumer : IConsumer<CreateStorageInformationSummary>
{
    private readonly IBus _serviceBus;
    private readonly USIntegrationQueueServiceContext _USIntegrationQueueServiceContext;


    public StorageInformationConsumer(IBus serviceBus, USIntegrationQueueServiceContext USIntegrationQueueServiceContext)
    {
        _serviceBus = serviceBus;
        _USIntegrationQueueServiceContext = USIntegrationQueueServiceContext;
    }

    public async Task Consume(ConsumeContext<CreateStorageInformationSummary> createStorageInformationSummarycontext)
    {
        //....
    }
}

And my Test like this

public class StorageInformationConsumerTest
{
    private readonly USIntegrationQueueServiceContext _dbContext;
    private readonly Mock<IBus> _serviceBusMock;
    private readonly StorageInformationConsumer _storageInformationConsumer;

    public StorageInformationConsumerTest()
    {
        var options = new DbContextOptionsBuilder<USIntegrationQueueServiceContext>()
                    .UseInMemoryDatabase(databaseName: "InMemoryArticleDatabase")
                    .Options;
        _dbContext = new USIntegrationQueueServiceContext(options);
        _serviceBusMock = new Mock<IBus>();
        _storageInformationConsumer = new StorageInformationConsumer(_serviceBusMock.Object, _dbContext);
    }

    [Fact]
    public async void ItShouldCreateStorageInformation()
    {
        var createStorageInformationSummary = new CreateStorageInformationSummary
        {
            ClaimNumber = "C-1234",
            WorkQueueItemId = 1,
            StorageInformation = CreateStorageInformation(),
        };

        //How to consume
    }
}

How to consume the CreateStorageInformationSummary message in order to call consumer, following doesn't work

var mockMessage = new Mock<ConsumeContext<CreateStorageInformationSummary>>(createStorageInformationSummary);
await _storageInformationConsumer.Consume(mockMessage.Object);

Lonnalonnard

What doesn't work? What is the expected behavior and actual behavior? – Vend

I was not mocking object correctly. – Lonnalonnard

Use the in-memory test harness instead, mocking is a fail since it won't really give you a true test on the message/consumer combination. See an example here: github.com/MassTransit/MassTransit/blob/develop/src/… – Spanking

Plus one on what Chris wrote. Use the MassTransit test harness, don't use mocks please. – Postoperative

Answer 1

Since you have not clarified what is actually not working, the most I can provide is how to create the mock context and pass it to the subject method under test.

This is simple enough since ConsumeContext<T> is already an interface

[Fact]
public async Task ItShouldCreateStorageInformation() {
    //Arrange
    var createStorageInformationSummary = new CreateStorageInformationSummary {
        ClaimNumber = "C-1234",
        WorkQueueItemId = 1,
        StorageInformation = CreateStorageInformation(),
    };
    //Mock the context
    var context = Mock.Of<ConsumeContext<CreateStorageInformationSummary>>(_ => 
        _.Message == createStorageInformationSummary);

    //Act
    await _storageInformationConsumer.Consume(context);

    //Assert
    //...assert the expected behavior
}

Also take note that the test has been updated to return async Task and not async void

Reference Moq Quickstart

Vend

Well, Message has no setter at least in my Mock version... Not working. Also you put == and guess you meant =. – Yonne

@VedranMandić The expression used in the mock is a predicate and not meant to assign an actual value hence the == – Vend