XUnit如何对业务对象进行单元测试，我应该模拟所有的东西吗？

Question

我正在尝试单元测试( Unit，XUnit)我的业务对象，其中它接受两个参数，并在返回输出之前执行一些操作。

    public OutPutModel MyBusinessObject(InputModel1 obj1, InputModel2 obj2)
    {
        // Performing some actions here including seding a call
        // to the data access layer to perform some db operation.
        return outPutModel;
    }

在我的XUnit中，我执行以下操作

    [Fact]
    public void MyBusinessObject_ReturnsOutPutModel()
    {
        var businessObjectMock = new Mock<IBusinessObject>();
        var obj1 = new Mock<InputModel1>();
        var obj2 = new Mock<InputModel2>();

        var outPutModel = new OutPutModel();

        var result = businessObjectMock.Setup(x => x.MyBusinessObject(obj1.Object, obj2.Object)).Returns(outPutModel);

        result.Equals(outPutModel);
    }

现在，我在业务对象(public OutPutModel MyBusinessObject(InputModel1 obj1，InputModel2 obj2))中设置了一个断点。在运行测试时，它不会到达断点，但仍然通过测试。我在这里做错什么了吗？我应该模拟所有东西，包括业务对象接口，还是仅仅模拟参数对象并调用业务对象的新实例？忘了提一下，我知道在业务对象中使用db级的东西不是个好主意。不幸的是，考虑到我别无选择。

Answer 1

您正在错误地使用模拟框架。您似乎也在试图模拟正在测试的系统。

经验法则，只有当使用实现具有敲门效应时，才能模拟绝对必要的内容。

例如，如果BusinessObject依赖于数据访问层，如您在代码注释中所指出的，

public class BusinessObject: IBusinessObject{

    private readonly IDataAccess dataAccess;

    public BusinessObject(IDataAccess dataAccess) {
        this.dataAccess = dataAccess;
    }

    public OutPutModel SomeBusinessMethod(InputModel1 obj1, InputModel2 obj2) {
        // Performing some actions here including seding a call
        // to the data access layer to perform some db operation.
        var outPutModel = dataAccess.SomeMethod(obj1, obj2);

        return outPutModel;
    }
}

您将模拟在被测试的方法中使用的依赖项，然后调用被测试类的实际实例。

例如

[Fact]
public void MyBusinessObject_ReturnsOutPutModel() {
    //Arrange
    var expected = new OutPutModel {
        // populate as needed
    }
    //mock the dependency
    var dataAccessMock = new Mock<IDataAccess>();
    //Setup the mocked dependency
    dataAccessMock
        .Setup(_ => _.SomeMethod(It.IsAny<InputModel1>(), It.IsAny<InputModel2>()))
        .Returns(expected);
    //inject the dependency into the subject under test
    var businessObject = new BusinessObject(dataAccessMock.Object);
    //needed objects for the test
    var obj1 = new InputModel1 {
        //populate as needed
    };
    var obj2 = new InputModel2 {
        //populate as needed
    };

    //Act
    var actual = businessObject.SomeBusinessMethod(obj1, obj2);

    //Assert
    Assert.AreEqual(expected, actual);
}