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Ploch.TestingSupport.XUnit3.AutoMoq

AutoFixture + AutoMoq integration for xUnit v3: one attribute to generate test data and auto-create Moq mocks for all dependencies.

Overview

Ploch.TestingSupport.XUnit3.AutoMoq removes the boilerplate of setting up AutoFixture with AutoMoqCustomization for every test class. It provides a single attribute — [AutoMockData] — that wires everything together: a fresh Fixture per test invocation, automatic generation of primitive values and populated objects, and Moq mocks for every interface or abstract class that appears as a constructor or method parameter.

The library also exposes the individual AutoFixture customizations used internally, so you can compose your own fixture when AutoMockDataAttribute does not match your exact needs.

Four customizations are included:

  • AutoDataCommonCustomization — combines AutoMoqCustomization, DoNotThrowOnRecursionCustomization, and OmitOnRecursionCustomization into a single convenience customization. Optionally adds IgnoreVirtualMembersCustomization.
  • DoNotThrowOnRecursionCustomization — removes AutoFixture's default ThrowingRecursionBehavior so that circular object graphs do not immediately raise an exception.
  • OmitOnRecursionCustomization — adds OmitOnRecursionBehavior so that recursive branches are silently omitted instead of throwing.
  • IgnoreVirtualMembersCustomization / IgnoreVirtualMembersSpecimenBuilder — instructs AutoFixture to omit virtual properties. Useful when the system under test has Moq-virtualized or EF Core lazy-loading proxy properties that must not be populated.

The project targets net8.0 and depends on Ploch.TestingSupport.XUnit3.Dependencies (which transitively provides AutoFixture.AutoMoq, AutoFixture.Xunit3, FluentAssertions, and Moq).

Installation

dotnet add package Ploch.TestingSupport.XUnit3.AutoMoq

Key Types

Type Description
AutoMockDataAttribute [AutoDataAttribute] preconfigured with AutoDataCommonCustomization. Apply to [Theory] methods to enable auto-generated test data and Moq mocks. Accepts ignoreVirtualMembers parameter.
AutoDataCommonCustomization ICustomization that composes AutoMoqCustomization, DoNotThrowOnRecursionCustomization, and OmitOnRecursionCustomization. Use directly when you need a custom Fixture.
DoNotThrowOnRecursionCustomization Removes ThrowingRecursionBehavior from the fixture's behaviour list.
OmitOnRecursionCustomization Adds OmitOnRecursionBehavior to handle recursive graphs by omission.
IgnoreVirtualMembersCustomization Adds IgnoreVirtualMembersSpecimenBuilder to the fixture. Accepts an optional Type to limit omission to a specific declaring type.
IgnoreVirtualMembersSpecimenBuilder ISpecimenBuilder that returns OmitSpecimen for virtual properties, optionally filtered by ReflectedType.

Usage Examples

Basic usage with [AutoMockData]

Decorate a [Theory] method with [AutoMockData]. AutoFixture generates the SUT and all dependencies. Interfaces and abstract classes arrive as Moq mocks.

[Theory]
[AutoMockData]
public void ProcessOrder_should_call_repository(OrderService sut, Mock<IOrderRepository> repositoryMock)
{
    // Arrange
    var order = new Order { Id = 1, Status = OrderStatus.Pending };
    repositoryMock.Setup(r => r.GetByIdAsync(1)).ReturnsAsync(order);

    // Act
    sut.Process(1);

    // Assert
    repositoryMock.Verify(r => r.SaveAsync(It.IsAny<Order>()), Times.Once);
}

Ignoring virtual members

Use the ignoreVirtualMembers: true parameter when the fixture populates EF Core navigation properties or Moq proxy members that should be left at their defaults:

[Theory]
[AutoMockData(ignoreVirtualMembers: true)]
public void Entity_should_have_valid_name(Customer customer)
{
    // AutoFixture populated Name and other non-virtual properties.
    // Virtual navigation properties (e.g. Orders) were omitted.
    customer.Name.Should().NotBeNullOrEmpty();
}

Composing a custom fixture

When you need more control than [AutoMockData] provides, build your own Fixture using AutoDataCommonCustomization:

public class MyCustomAutoData : AutoDataAttribute
{
    public MyCustomAutoData() : base(() =>
    {
        var fixture = new Fixture();
        fixture.Customize(new AutoDataCommonCustomization(ignoreVirtualMembers: false));
        fixture.Register<ISpecialService>(() => new FakeSpecialService());
        return fixture;
    })
    { }
}

Using individual customizations

Apply just the recursion-handling customizations to an existing fixture:

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

Limit virtual member omission to a single type:

fixture.Customize(new IgnoreVirtualMembersCustomization(typeof(MyEntity)));
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