c# - 断言表达式

Question

我有一个“示例”类，我想为它创建单元测试。看看下面我的类(class):

public class Example 
{
    private readonly Calculator _calculator;

    public Example(ICalculator calculator)
    {
        _calculator = calculator;
    }

    public void Calculate()
    {
        _calculator.Execute(operation => operation.Subtract());
    }
}

public interface IOperation { 
    void Sum();
    void Subtract();
}

public inferface ICalculator { 
    void Execute(Action<IOperation> action);
}

public class Calculator {
    public void Execute(Action<IOperation> action){}
}

我想要的是创建一个单元测试类来验证我的示例类 Calculate 中的方法调用 _calculator.Execute 作为参数传递 操作。减去()。可能吗？

我知道如何模拟我的 ICalculator 并验证 Execute 被调用一次，但我不知道如何验证 Execute 方法是否被调用 operation.Subtract() 作为参数而不是 operation.Sum()。

我正在使用 NUnit 创建我的单元测试。在这里您可以看到我的单元测试类目前的情况:

[TestFixture]
public class ExampleTests 
{
    [Test]
    public void Test1()
    {
        var calculator = new Mock<ICalculator>();
        var subject = new Example(calculator.Object);

        subject.Calculate();

        calculator.Verify(x => x.Execute(It.IsAny<Action<IOperation>>()), Times.Once);
    }
}

希望有人能听懂我的英文，抱歉。

Answer 1

您无法直接验证传递的是什么 lambda，但您可以通过实际调用 said lambda 和另一个模拟来绕过它:

var calculator = new Mock<ICalculator>();
var operation = new Mock<IOperation>();
// when calculator's Execute is called, invoke it's argument (Action<IOperation>)
// with mocked IOperation which will later be verified
calculator
    .Setup(c => c.Execute(It.IsAny<Action<IOperation>>()))
    .Callback<Action<IOperation>>(args => args(operation.Object));
var example = new Example(calculator.Object);

example.Calculate();

calculator.Verify(c => c.Execute(It.IsAny<Action<IOperation>>()));
operation.Verify(o => o.Subtract());