Question

我投入了大量时间并且已经看到了不同的答案，但不知道什么是错的，无论我做什么，我总是得到返回值null。

我希望Return值是一个对象（模拟对象等），我可以在其上执行Assert操作。如果我在理解这个概念的错误轨道上请告诉我。

[Fact]
public void ProjectTest()
{
    var ProjectServiceMock = new Mock<IProjectService>();
    var ProjectMock = new Mock<IProject>();
    IProject project = ProjectMock.Object;
    ProjectServiceMock.Setup(x => x.CreateProject(new Path("C:"), "S1")).Returns(project);
    var addProjectViewModel = new AddProjectViewModel(ProjectServiceMock.Object);

    IProjectService obj = ProjectServiceMock.Object;
    var result = obj.CreateProject(new Path("C:"), "S1");
}

result始终为null。

Answer 1

您正在设置和模拟调用之间传递两个单独的实例，因此默认情况下它将返回null。

您要么使用相同的实例

[Fact]
public void ProjectTest() {
    var ProjectServiceMock = new Mock<IProjectService>();
    var ProjectMock = new Mock<IProject>();
    IProject project = ProjectMock.Object;
    var path = new Path("C:");
    ProjectServiceMock.Setup(x => x.CreateProject(path, "S1")).Returns(project);
    var addProjectViewModel = new AddProjectViewModel(ProjectServiceMock.Object);

    IProjectService obj = ProjectServiceMock.Object;
    var result = obj.CreateProject(path, "S1");
}

或者使用它的参数匹配器与实际的参数实例

无关

[Fact]
public void ProjectTest() {
    var ProjectServiceMock = new Mock<IProjectService>();
    var ProjectMock = new Mock<IProject>();
    IProject project = ProjectMock.Object;
    ProjectServiceMock.Setup(x => x.CreateProject(It.IsAny<Path>(), "S1")).Returns(project);
    var addProjectViewModel = new AddProjectViewModel(ProjectServiceMock.Object);

    IProjectService obj = ProjectServiceMock.Object;
    var result = obj.CreateProject(new Path("C:"), "S1");
}

完成后，观察到基本上是在尝试测试模拟框架。在提供的示例中没有测试实际代码。

尝试按照测试的AAA方法

[Fact]
public void ProjectTest() {
    //Arrange
    var ProjectServiceMock = new Mock<IProjectService>();
    var ProjectMock = new Mock<IProject>();
    IProject project = ProjectMock.Object;
    ProjectServiceMock
        .Setup(x => x.CreateProject(It.IsAny<Path>(), "S1"))
        .Returns(project);
    //System under test
    var addProjectViewModel = new AddProjectViewModel(ProjectServiceMock.Object);

    //Act
    addProjectViewModel.SomeMethodToTest();
    //...assumption is that `CreateProject(new Path("C:"), "S1")` will get called within
    //...the method under test

    //Assert
    //...now assert expected behavior        
}

参考Moq Quickstart以更好地理解如何使用该模拟框架

返回始终为null moq

1 个答案: