单元测试中动态转换失败的通用解决方案

Question

I'm working on a .NET Core 5 application. In some parts of the system, I'm using a cast to dynamic to handle generic type resolution. Something like this:

public void Foo(ISomething something){
    Bar((dynamic)something);
}

private void Bar<T>(T somethingElse) where T : ISomething
{ .... }

Works pretty well if I run the whole application. Now, for some mysterious reason, the same code refuses to work during Unit Tests. I get an exception as soon as it tries to call Bar<T>() , complaining that it's receiving an object instead of an ISomething . I'm using XUnit.

Any idea?

UPDATE 10/01/2021 I've pushed the code to GitHub , the branch is coverage .

This is the failing test. The issue happens on this line in the InMemoryPublisher class, when casting the message to dynamic.

Answer 1

ok, I found the issue. I had marked the ISomething implementations as internal . Switching to public fixed it.