最小起订量以验证某些不可预测的值

Question

为了方便解释，我有以下代码

public interface IAnother
{
    void DoAnotherJob(DateTime date);
}

public class MainJob
{
    private IAnother another;

    public MainJob(IAnother another)
    {
        this.another = another;
    }

    public void FunctionA()
    {
        this.FunctionB(DateTime.Now);
    }

    public void FunctionB(DateTime date)
    {
        this.another.DoAnotherJob(date);
    }
}

我需要编写单元测试代码以确保在调用 FunctionA() 时底层 IAnother.DoAnotherJob() 被调用以使用当前日期时间。

我会写测试代码

    [TestMethod()]
    public void FunctionATest()
    {
        var mockAnother = new Mock<IAnother>();

        var mainJob = new MainJob(mockAnother.Object);

        mainJob.FunctionA();

        mockAnother.Verify(x => x.DoAnotherJob(It.IsAny<DateTime>()), Times.Once);
    }

确保函数在任何日期时间被调用，但我无法指定确切的值，因为 DateTime 的实际值不可预测。

有什么想法吗？

Answer 1

当您想要验证有关 DateTime.Now 的任何内容时，您总是会遇到困难，因为属性值很可能会在两次调用之间发生变化。你能做的最好的事情是这样的：

mockAnother.Verify(x => x.DoAnotherJob(It.Is<DateTime>(d > DateTime.Now.AddSeconds(-1))), Times.Once);

另一种方法是引入另一个 class 和用于解析 DateTime:

的抽象

public interface ITimeProvider
{
    DateTime Now { get; }
}

public class TimeProvider : ITimeProvider
{
    DateTime Now { get { return DateTime.Now ; } }
}

然后您将直接使用而不是 DateTime.Now：

public class MainJob
{
    private IAnother another;
    private ITimeProvider timeProvider;

    public MainJob(IAnother another, ITimeProvider timeProvider)
    {
        this.another = another;
        this.timeProvider = timeProvider;
    }

    public void FunctionA()
    {
        this.FunctionB(this.timeProvider.Now);
    }

    public void FunctionB(DateTime date)
    {
        this.another.DoAnotherJob(date);
    }
}

然后，你的单元测试变成：

[TestMethod()]
public void FunctionATest()
{
    var now = DateTime.Now;
    var mockAnother = new Mock<IAnother>();
    var mockTimeProvider = new Mock<ITimeProvider>();
    mockTimeProvider.Setup(x => x.Now).Returns(now);

    var mainJob = new MainJob(mockAnother.Object, mockTimeProvider.Object);

    mainJob.FunctionA();

    mockAnother.Verify(x => x.DoAnotherJob(now), Times.Once);
}

最小起订量以验证某些不可预测的值

Moq to verify certain value not predicable

c#

unit-testing

moq