如何设置moq模拟以引发在接口实现中定义的事件，而不是接口本身？

Question

The code to be mocked looks like this:

class Foo : IBar
{
    public virtual event EventHandler FooEventHandler;

    void FooMethod()
    {
        // blah, blah, blah...
    }

    void IBar.BarMethod()
    {
        this.FooEventHandler?.Invoke(this, new EventArgs()); 
    }
}

interface IBar 
{
    void BarMethod();
}

I want to mock Foo and its implementation of IBar so that I can hand it to the subject under test and assert. Requirements tell me that I'm not allowed to put the event handler on the IBar interface, so the explanation behind this link doesn't seem to work for me.

Answer 1

Edit:

I'm trying to add clarity here, but I'm not sure it's working.

Using Mock.As<T>() method allows one to create a mock that follows multiple interfaces. With requirements that the event signature can't live on the IBar interface, I am mocking the concrete Foo class and then assigning IBar to the mock using .As<IBar>() . The return of .As<IBar> allows me to setup the .BarMethod() for raising an event with the .Raises(...) method accepting a lambda expression on the mock of IBar . In this expression, using .As<Foo>() allows access back to the virtual event handler on the concrete being mocked withing the context of setting up IBar .

var foo = new Mock<Foo>();
foo.As<IBar>()
   .Setup(bar => bar.BarMethod())
   .Raises(bar => bar.As<Foo>().FooEventHandler += null, new EventArgs());