asp.net-mvc - 使用 Moq 单元测试 Builder 模式

Question

我正在使用构建器模式为 Controller 生成 View 模型，当我尝试对 Controller 进行单元测试时，我发现自己无法这样做。起订量提示。

不确定这是起订量限制还是我自己的限制和无知。

这是我的 Controller 的样子:

public class OutletController : Controller
{
    private readonly IOutletViewModelBuilder _builder;

    public OutletController(IOutletViewModelBuilder builder)
    {
        this._builder = builder;
    }


    public ActionResult Edit(int id)
    {
        OutletViewModel viewModel = this._builder.WithOutlet(id).WithCountryList().Build();

        return View(viewModel);
    }
}

我试图 mock IOutletViewModelBuilder 对象，但这就是我得到的:

[Test]
public void DummyTest()
{
    Mock<IOutletViewModelBuilder> mockBuilder = new Mock<IOutletViewModelBuilder>();
    // (1) // mockBuilder.Setup(m => m.WithOutlet(It.IsAny<int>())).Returns(mockBuilder.Object);
    // (2) //mockBuilder.Setup(m => m.WithOutlet(It.IsAny<int>())).Returns(mockBuilder);

    // (3) // mockBuilder.Setup(m => m.WithOutlet(It.IsAny<int>()).WithCountryList().Build()).Returns(new OutletViewModel());

    OutletController controller = new OutletController(mockBuilder.Object);
    ActionResult result = controller.Edit(1);

    Assert.IsTrue(true);
}

(1) 给了我以下错误突出显示(mockBuilder.Object)

无法解析方法“Returns(ViewModelBuilders.Builders.IOutletViewModelBuilder)”，候选对象是:

Moq.Language.Flow.IReturnsResult<ViewModelBuilders.Builders.IOutletViewModelBuilder> Returns(System.Func<ViewModelBuilders.Builder.IOutletViewModelBuilder>) (in interface IReturns<IOutletViewModelBuilder,OutletViewModelBuilder>)
Moq.Language.Flow.IReturnsResult<ViewModelBuilders.Builders.IOutletViewModelBuilder> Returns(ViewModelBuilders.Builders.OutletViewModelBuilder) (in interface IReturns<IOutletViewModelBuilder,OutletModelBuilder>)

(2) 引发以下错误:

无法解析方法“Returns(Moq.Mock)”，候选对象是:

Moq.Language.Flow.IReturnsResult<ViewModelBuilders.Builders.IOutletViewModelBuilder> Returns(System.Func<ViewModelBuilders.Builders.OutletViewModelBuilder>) (in interface IReturns<IOutletViewModelBuilder,OutletViewModelBuilder>)
Moq.Language.Flow.IReturnsResult<ViewModelBuilders.Builders.IOutletViewModelBuilder> Returns(ViewModelBuilders.Builders.OutletViewModelBuilder) (in interface IReturns<IOutletViewModelBuilder,OutletViewModelBuilder>)

(3) 不会引发编译时错误，而是引发运行时错误:

System.NotSupportedException : Invalid setup on a non-virtual (overridable in VB) member: m => m.WithOutlet(It.IsAny<Int32>()).WithCountryList().Build()
at Moq.Mock.ThrowIfCantOverride(Expression setup, MethodInfo method)
at Moq.Mock.<>c__DisplayClass1c`2.<Setup>b__1b()
at Moq.Mock.Setup(Mock mock, Expression`1 expression, Func`1 condition)
at ViewModelBuilderTests.OutletControllerTest.DummyTest() 

任何帮助将不胜感激。对这个方法进行单元测试应该不难吧？

如果您需要查看实现，您可以在下方看到 Builder 对象。

public class OutletViewModelBuilder
{
    private readonly IRepository _repository;
    private OutletViewModel _viewModel;

    public OutletViewModelBuilder(IRepository repository)
    {
        this._repository = repository;
        this._viewModel = new OutletViewModel();
    }

    public OutletViewModel Build()
    {
        return this._viewModel;
    }

    public OutletViewModelBuilder WithOutlet(int outletId)
    {
        this._viewModel.Outlet = this._repository.GetOutletById(outletId);

        return this;
    }

    public OutletViewModelBuilder WithCountryList()
    {
        this._viewModel.CountryList = this._repository.GetCountryList();

        return this;
    }
}

最后， IOutletViewModelBuilder 界面

public interface IOutletViewModelBuilder
{
    OutletViewModel Build();

    OutletViewModelBuilder WithOutlet(int outletId);

    OutletViewModelBuilder WithCountryList();
}

Answer 1

看起来主要问题是您的 WithOutlet 和 WithCountryList 方法返回的是具体的 OutletViewModelBuilder 而不是 IOutletViewModelBuilder。我想你需要这样的东西:

public interface IOutletViewModelBuilder
{
    OutletViewModel Build();
    IOutletViewModelBuilder WithOutlet(int outletId);
    IOutletViewModelBuilder WithCountryList();
}

那么你的 mock :

var myViewModel = TheOutletViewModelForTesting();
var mockBuilder = new Mock<IOutletViewModelBuilder>();

mockBuilder.Setup(m => m.WithOutlet(It.IsAny<int>())).Returns(mockBuilder.Object);
mockBuilder.Setup(m => m.WithCountryList()).Returns(mockBuilder.Object);
mockBuilder.Setup(m => m.Build()).Returns(myViewModel);

// rest of your test that validates that myViewModel is passed correctly to your view