如何验证返回模拟的函数工厂的调用？

如何解决如何验证返回模拟的函数工厂的调用？

被测系统 (Sut) 采用两个参数 Func<IFoo> 和 IBar。在 Sut 内部实例化 IFoo 的对象，然后调用 foo 和 _bar。

public class Sut : ISut
{
    readonly Func<IFoo> _fooFactory;
    IBar _bar;
    
    public Sut(Func<IFoo> fooFactory,IBar bar)
    {
        _fooFactory = fooFactory;
        _bar = bar;
    }
    
    public SutMethod()
    {
        foo = _fooFactory();
        foo.fooMethod();
        
        _bar.barMethod();
    }
}

然后使用其模拟 _bar 来测试 barMock 的调用。但是我如何测试 foo？我怎么能说 foo 是

1. 实例化和
2. 叫

？

public class Test
{
    Func<Func<IFoo>,IBar,ISut> _sutFactory;
    
    public Test(Func<Func<IFoo>,ISut> sutFactory)
    {
        _sutFactory = sutFactory;
    }

    [Fact]
    public void TestCase()
    {
    
        Func<IFoo> fooFactory = () =>
        {
            var mock => new Mock<IFoo>();
            mock.Setup(x => x.fooMethod();
            return mock.Object;
        }   

        Mock<IBar> barMock = new Mock<IBar>();
        
        sut = _sutFactory(fooFactory,barMock);
        sut.SutMethod();
        
        barMock.Verify(mock => mock.barMethod(),Times.Once());
    }   
}

解决方法

在工厂委托之外创建模拟，以便您可以访问它进行验证

public class Test {
    Func<Func<IFoo>,IBar,ISut> _sutFactory;
    
    public Test(Func<Func<IFoo>,ISut> sutFactory) {
        _sutFactory = sutFactory;
    }

    [Fact]
    public void TestCase() {
        //Arrange
        Mock<IFoo> fooMock = null;
            
        Func<IFoo> fooFactory = () => {
            fooMock = new Mock<IFoo>();
            return fooMock.Object;
        }

        Mock<IBar> barMock = new Mock<IBar>();
        
        ISut sut = _sutFactory(fooFactory,barMock);

        //Act
        sut.SutMethod();
        
        //Assert
        barMock.Verify(mock => mock.barMethod(),Times.Once());
        // 1. instantiated
        Assert.IsNotNull(fooMock);
        // 2. called
        fooMock.Verify(mock => mock.fooMethod(),Times.Once());
    }   
}