UnitTests - Moq - 如何从与 Setup() 中的参数匹配的 Moq 返回() 对象

Question

我对 Moq 感到困惑，我不确定这里有什么问题。

我想测试依赖于 ILeadStorageService 的 LeadService，并且我想以这种方式配置 Moq - 返回与安装程序中传递的 GUID 匹配的对象。

问题出在 Moq Setup/Returns 行中，因为当我将依赖对象替换为其真实实例时 - 测试通过，但完全错误。我不想只测试 LeadService，而不是从属存储。

    public LeadService( IConfigurationDbContext configurationDbContext, 
                        ILeadStorageService leadStorageService,
                        ILeadDeliveryService deliveryService)
    {
        this.configurationDbContext = configurationDbContext;
        this.leadStorageService = leadStorageService;
        this.deliveryService = deliveryService;

    }

测试方法

        public TestLeadResponse ProcessTestLead(TestLeadRequest request)
        {
        var response = new TestLeadResponse()
        {
            Status = TestLeadStatus.Ok
        };

        try
        {
            var lead = leadStorageService.Get(request.LeadId);
            if (lead == null)
            {
                throw new LeadNotFoundException(request.LeadId);
            }

            var buyerContract =
                configurationDbContext.BuyerContracts.SingleOrDefault(bc => bc.Id == request.BuyerContractId);
            if (buyerContract == null)
            {
                throw new BuyerContractNotFoundException(request.BuyerContractId);
            }

            response.DeliveryEntry = deliveryService.DeliverLead(lead, buyerContract);
        }
        catch (LeadNotFoundException e)
        {
            response.Status = TestLeadStatus.LeadNotFound;
            response.StatusDescription = e.Message;
        }
        catch (BuyerContractNotFoundException e)
        {
            response.Status = TestLeadStatus.BuyerContractNotFound;
            response.StatusDescription = e.Message;
        }

        return response;
    }

然后在测试准备中：

    [TestInitialize]
    public void Initialize()
    {
        _leadIdStr = "2c3ac0c0-f0c2-4eb0-a55e-600ae3ada221";

        _dbcontext = new ConfigurationDbContext();
        _lead = PrepareLeadObject();
        _buyerContract = PrepareBuyerContractObject(Id : 1, BuyerContractId :  1, BuyerTag: "GAME");
        _leadDeliveryMock = new Mock<ILeadDeliveryService>();
        _leadStorageMock = new Mock<ILeadStorageService>();
        _leadStorageService = new LeadStorageService("LeadGeneration_Dev");

    }

    private Lead PrepareLeadObject()
    {
        var lead = new Lead() {CountryId = 1, Country = "NL", Id = Guid.Parse(_leadIdStr)};
        return lead;

    }

和测试本身：

    [TestMethod]
    public void LeadServiceTest_ProcessTestLeadWithWrongBuyerContractIDThrowsBuyerContractNotFoundException()
    {
        _leadDeliveryMock
            .Setup(methodCall => methodCall.DeliverLead(_lead, _buyerContract))
            .Returns<LeadDeliveryEntry>((r) => PrepareLeadDeliveryEntry());

        // here is the problem!!!!
        _leadStorageMock.Setup(mc => mc.Get(_leadId)).Returns((Lead l) => PrepareLeadObject());

        //if i change to real object - test passes
        //_service = new LeadService(_dbcontext, _leadStorageService, _leadDeliveryMock.Object);
        _service = new LeadService(_dbcontext, _leadStorageMock.Object, _leadDeliveryMock.Object);

        var response = _service.ProcessTestLead(new TestLeadRequest() { BuyerContractId = int.MaxValue, LeadId = _leadId });

        Assert.IsNotNull(response);
        Assert.AreEqual(response.Status, TestLeadStatus.BuyerContractNotFound);

    }

而不是预期的回报 - 我有一个例外：

我在 _leadStorageMock.Setup().Returns() 中缺少什么？

Answer 1

Returns扩展方法接受一个与您正在模拟的方法具有相同参数的委托。这些参数将在调用模拟方法期间传递给委托。因此Lead，您将获得传递给mc.Get方法的参数而不是对象- 潜在客户 ID：

_leadStorageMock.Setup(mc => mc.Get(_leadId))
      .Returns((Guid leadId) => PrepareLeadObject());

检查与返回值时访问调用参数相关的快速入门部分。

请注意，有一堆Returns扩展方法接受值函数作为参数：

Returns<T>(Func<T, TResult> valueFunction);
Returns<T1, T2>(Func<T1, T2, TResult> valueFunction);
Returns<T1, T2, T3>(Func<T1, T2, T3, TResult> valueFunction);
// etc

如您所见，这些值函数计算从模拟方法返回的值，但它们都接收不同数量的参数（最多 16 个）。这些参数将与您正在模拟的方法的参数完全匹配，并且它们将在被valueFunction模拟方法的调用期间传递给。因此，如果您使用两个参数模拟某个函数，则应使用相应的扩展名：

mock.Setup(m => m.Activate(It.IsAny<int>(), It.IsAny<bool>())
    .Returns((int i, bool b) => b ? i : 0); // Func<T1, T2, TResult>