单元测试与Moq的Builder模式

Question

我正在使用构建器模式为控制器生成视图模型,当我尝试对控制器进行单元测试时,我发现自己无法这样做.Moq抱怨道.

不确定这是Moq限制还是我自己的限制和无知.

这就是我的控制器的样子:

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);
    }
}

我试图模拟IOutletViewModelBuilder对象,但这是我得到的:

[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)给我以下错误突出显示(mockBuilder.Object)

无法解析方法'返回(ViewModelBuilders.Builders.IOutletViewModelBuilder)',候选人是:

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)抛出以下错误:

无法解析方法'返回(Moq.Mock)',候选人是:

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)不抛出编译时错误而是运行时错误:

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.应该对这种方法进行单元测试是不是很难,是吗？

您可以在下面看到Builder对象,以防您需要查看实现.

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接口

public interface IOutletViewModelBuilder
{
    OutletViewModel Build();

    OutletViewModelBuilder WithOutlet(int outletId);

    OutletViewModelBuilder WithCountryList();
}

Answer 1

看起来主要的问题是你的WithOutlet和WithCountryList方法返回一个具体的OutletViewModelBuilder,而不是返回一个IOutletViewModelBuilder.我想你需要这样的东西:

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

然后你的嘲笑:

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