AutoFixture: mock methods don't return a frozen instance

Question

I\'m trying to write this simple test:

var fixture = new Fixture().Customize(new AutoMoqCustomization());

var pos         


        

Answer 1

You need to Freeze the IPostProcessingActionReader component.

The following test will pass:

[Fact]
public void Test()
{
    var fixture = new Fixture()
        .Customize(new AutoMoqCustomization());

    var postProcessingActionMock = new Mock<IPostProcessingAction>();

    var postProcessingActionReaderMock = fixture
        .Freeze<Mock<IPostProcessingActionReader>>();

    postProcessingActionReaderMock
        .Setup(x => x.CreatePostProcessingActionFromJobResultXml(
            It.IsAny<string>()))
        .Returns(postProcessingActionMock.Object);

    var postProcessor = fixture.CreateAnonymous<PostProcessor>();
    postProcessor.Process("", "");

    postProcessingActionMock.Verify(action => action.Do());
}

Assuming that the types are defined as:

public interface IPostProcessingAction
{
    void Do();
}

public class PostProcessor
{
    private readonly IPostProcessingActionReader actionReader;

    public PostProcessor(IPostProcessingActionReader actionReader)
    {
        if (actionReader == null)
            throw new ArgumentNullException("actionReader");

        this.actionReader = actionReader;
    }

    public void Process(string resultFilePath, string jobId)
    {
        IPostProcessingAction postProcessingAction = this.actionReader
            .CreatePostProcessingActionFromJobResultXml(resultFilePath);

        postProcessingAction.Do();
    }
}

public interface IPostProcessingActionReader
{
    IPostProcessingAction CreatePostProcessingActionFromJobResultXml(
        string resultFilePath);
}

---

In case you use AutoFixture declaratively with the xUnit.net extension the test could be simplified even further:

[Theory, AutoMoqData]
public void Test(
    [Frozen]Mock<IPostProcessingActionReader> readerMock,
    Mock<IPostProcessingAction> postProcessingActionMock,
    PostProcessor postProcessor)
{
    readerMock
        .Setup(x => x.CreatePostProcessingActionFromJobResultXml(
            It.IsAny<string>()))
        .Returns(postProcessingActionMock.Object);

    postProcessor.Process("", "");

    postProcessingActionMock.Verify(action => action.Do());
}

The AutoMoqDataAttribute is defined as:

internal class AutoMoqDataAttribute : AutoDataAttribute
{
    internal AutoMoqDataAttribute()
        : base(new Fixture().Customize(new AutoMoqCustomization()))
    {
    }
}

Answer 2

As of 3.20.0, you can use AutoConfiguredMoqCustomization. This will automatically configure all mocks so that their members' return values are generated by AutoFixture.

In other words, it will auto-configure your postProcessingActionReader to return the frozen postProcessingAction.

Just change this:

var fixture = new Fixture().Customize(new AutoMoqCustomization());

to this:

var fixture = new Fixture().Customize(new AutoConfiguredMoqCustomization());