Question

对于我的一个作业，我必须制作一个方法，该方法将使用IRepository作为基础从数据库返回下一个项目。我正在使用TDD设计周期，到目前为止，这就是我所拥有的：

    [TestMethod]
    public void ShouldReturnNextExportRequest()
    {
        var requests = new List<ExportRequest>();

        for (var i = 0; i < 100; i++)
        {
            var exportRequest = new Mock<ExportRequest>();
            exportRequest.SetupGet(req => req.Id).Returns(i);

            requests.Add(exportRequest.Object);
        }

        // Over-writing variables is bad
        requests = requests.OrderBy(er => er.Id).ToList();

        /**
         * Mock the IRepository so that the Min() call returns the export request with the minimum Id
         */
        var repo = new Mock<IRepository<ExportRequest>>();
        repo.Setup(rep => rep.Min(It.IsAny<Expression<Func<ExportRequest, int>>>()))
            .Returns<Expression<Func<ExportRequest, int>>>(expr => requests.Min(e => e.Id));

        repo.Setup(rep => rep.Get(It.IsAny<int>())).Returns<int>(requests.ElementAt);
        repo.Setup(rep => rep.Delete(It.IsAny<ExportRequest>()))
            .Callback<ExportRequest>(req => Assert.IsTrue(requests.Remove(req), "Couldn't remove {0} from list", req.Id));


        var exportRequestRepository = new ExportRequestRepository(repo.Object);
        exportRequestRepository.GetNextRequest();
        exportRequestRepository.GetNextRequest();

        var third = exportRequestRepository.GetNextRequest();
        var top = requests.First();
        Assert.AreEqual(top.Id, third.Id, "Top element in list has id of {0}, but return from repository is {1}", top.Id, third.Id);
    }

GetNextRequest()方法只是这样做：

    public ExportRequest GetNextRequest()
    {
        var top = _exportRequestRepository.Min(er => er.Id);
        var element = _exportRequestRepository.Get(top);
        _exportRequestRepository.Delete(element);
        return element;
    }

这一切都运行得很好，但是第二个元素 - id为1 - 永远不会从列表中删除。我已经解决了IEnumerable.Min List上的Test Name: ShouldReturnNextExportRequest Test FullName: ExportService.Tests.ExportRequestRepositorySpecification.ShouldReturnNextExportRequest Test Source: c:\Users\dan.pantry\Desktop\RUMM\ExportService.Tests\ExportRequestRepositorySpecification.cs : line 17 Test Outcome: Failed Test Duration: 0:00:00.211873 Result Message: Assert.AreEqual failed. Expected:<1>. Actual:<3>. Top element in list has id of 1, but return from repository is 3 Result StackTrace: at ExportService.Tests.ExportRequestRepositorySpecification.ShouldReturnNextExportRequest() in c:\Users\dan.pantry\Desktop\RUMM\ExportService.Tests\ExportRequestRepositorySpecification.cs:line 49实现，因为它似乎永远不会返回Id为1的元素（通过在调试模式下查看List来确定）。 / p>

我错过了一些明显的东西吗？

注意：我正在使用来自SharpRepository的模拟IRepository。并不是说它有所作为，因为Moq-ed接口没有固有的动作，但值得注意。

编辑：测试输出。

        repo.Setup(rep => rep.Get(It.IsAny<int>())).Returns<int>(requests.ElementAt)
            .Callback<int>(req => Console.WriteLine("Retrieved {0}", req));

EDIT2：所以我对Get（）进行回调，如下所示：

Retrieved 0
Retrieved 1
Retrieved 1

现在我的输出看起来有点像这样：

GetNextRequest()

EDIT3：以下是public ExportRequestRepository(IRepository<ExportRequest> exportRequestRepository) { _exportRequestRepository = exportRequestRepository; }中_exportRequestRepository的来源 - 在测试中它是模拟的存储库并被注入构造函数

{{1}}

Answer 1

问题解决了。问题是，当我应该使用ElementAt时，我正在使用Find，并且我在First()之前调用GetNextRequest()（获取下一个请求“弹出”元素来自底层存储库 - 可能会改变它。）

        var repo = new Mock<IRepository<ExportRequest>>();
        repo.Setup(rep => rep.Min(It.IsAny<Expression<Func<ExportRequest, int>>>()))
            .Returns<Expression<Func<ExportRequest, int>>>(expr => requests.Min(e => e.Id));

        repo.Setup(rep => rep.Get(It.IsAny<int>())).Returns<int>(i => requests.Find(er => er.Id == i));

        repo.Setup(rep => rep.Delete(It.IsAny<ExportRequest>()))
            .Callback<ExportRequest>(req => Assert.IsTrue(requests.Remove(req), "Couldn't remove {0} from list", req.Id));


        var exportRequestRepository = new ExportRequestRepository(repo.Object);

        Assert.AreEqual(0, exportRequestRepository.GetNextRequest().Id);
        Assert.AreEqual(1, exportRequestRepository.GetNextRequest().Id);

        var top = requests.First();
        var third = exportRequestRepository.GetNextRequest();

        Assert.AreEqual(top.Id, third.Id, "Top element in list has id of {0}, but return from repository is {1}", top.Id, third.Id);

解决的代码如上。如您所见，Get现在使用requests.Find()而不是requests.ElementAt

为什么我的模拟列表没有删除某个元素？

1 个答案: