如何解决来自 RhinoMocks 的 System.InvalidOperationException？答案

【问题标题】：How to solve System.InvalidOperationException from RhinoMocks?如何解决来自 RhinoMocks 的 System.InvalidOperationException？
【发布时间】：2015-08-26 07:59:05
【问题描述】：

出于测试目的，我使用 NUnit 和 RhinoMocks。昨天发生了一个错误，我无法解决它。我在互联网上搜索了解决方案。我找到了很多可能的解决方案，但就我而言，它并没有解决问题。

异常堆栈跟踪：

   System.InvalidOperationException : Previous method 'IContainer.GetImageHandler();' requires a return value or an exception to throw.
   at Rhino.Mocks.Impl.RecordMockState.AssertPreviousMethodIsClose()
   at Rhino.Mocks.Impl.RecordMockState.Replay()
   at Rhino.Mocks.MockRepository.ReplayCore(Object obj, Boolean checkInsideOrdering)
   at Rhino.Mocks.RhinoMocksExtensions.Expect(T mock, Function`2 action)
   at ImageControllerTest.UnitTests.ImageControllerTest.SmokeTest()

代码：

    [TestFixture]
public class ImageControllerTest
{
    [Test]
    public void SmokeTest()
    {
        var container = MockRepository.GenerateStrictMock<IContainer>();
        var imageController = new ImageController(container);

        string imagePhysicalLocation = @"c:\image.jpg";

        Stream imageStream = null;
        container.Expect(x => x.GetImageHandler().LoadImage(imagePhysicalLocation)).Repeat.Once().Return(imageStream);

        container.Expect(x => x.GetImageHandler().ConvertToGrayScale(imageStream)).Repeat.Once().Return(imageStream);

        var dimensions = new KeyValuePair<int, int>(200, 200);

        container.Expect(x => x.GetImageHandler().GetDimensions(imageStream)).Repeat.Once().Return(dimensions);

        imageController.Execute(imagePhysicalLocation);

        container.VerifyAllExpectations();
    }
}

public interface IContainer
{
    IImageHandler GetImageHandler();
}

public interface IImageHandler
{
    Stream LoadImage(string physicalLocation);
    KeyValuePair<int, int> GetDimensions(Stream image);
    Stream ConvertToGrayScale(Stream image);
}

public class ImageController
{
    private readonly IContainer container;

    public ImageController(IContainer container)
    {
        this.container = container;
    }

    public void Execute(string imagePhysicalLocation)
    {
        Stream image = container.GetImageHandler().LoadImage(imagePhysicalLocation);

        Stream imageInGrayScale = container.GetImageHandler().ConvertToGrayScale(image);

        container.GetImageHandler().GetDimensions(imageInGrayScale);
    }
}

有人知道我该如何解决这个错误吗？

非常感谢。

乔迪

【问题讨论】：

标签： c# .net unit-testing nunit rhino-mocks

【解决方案1】：

您将需要另一个模拟您的 ImageHandler，就像这样：

[TestFixture]
public class ImageControllerTest
{
    [Test]
    public void SmokeTest()
    {
        var container = MockRepository.GenerateStrictMock<IContainer>();
        var handler = MockRepository.GenerateStrictMock<IImageHandler>();
        var imageController = new ImageController(container);

        string imagePhysicalLocation = @"c:\image.jpg";

        Stream imageStream = null;

        container.Expect(x => x.GetImageHandler()).Return(handler);


        handler.Expect(x => x.LoadImage(imagePhysicalLocation)).Repeat.Once().Return(imageStream);

        handler.Expect(x => x.ConvertToGrayScale(imageStream)).Repeat.Once().Return(imageStream);

        var dimensions = new KeyValuePair<int, int>(200, 200);

        handler.Expect(x => x.GetDimensions(imageStream)).Repeat.Once().Return(dimensions);

        imageController.Execute(imagePhysicalLocation);

        container.VerifyAllExpectations();
        handler.VerifyAllExpectations();
    }
}

public interface IContainer
{
    IImageHandler GetImageHandler();
}

public interface IImageHandler
{
    Stream LoadImage(string physicalLocation);
    KeyValuePair<int, int> GetDimensions(Stream image);
    Stream ConvertToGrayScale(Stream image);
}

public class ImageController
{
    private readonly IContainer container;

    public ImageController(IContainer container)
    {
        this.container = container;
    }

    public void Execute(string imagePhysicalLocation)
    {
        Stream image = container.GetImageHandler().LoadImage(imagePhysicalLocation);

        Stream imageInGrayScale = container.GetImageHandler().ConvertToGrayScale(image);

        container.GetImageHandler().GetDimensions(imageInGrayScale);
    }
}

祝你好运！

【讨论】：