I think these type of tests are not about “testing for finding bugs” but about “testing for giving quick feedback if it works as before”.
The discussion about is it too much coupling between test and production code is valuable. But as for me unit tests are just your production code that never present in the app. As any production code it have to be changes as soon as dependency code changed. And we all are trying to learn art how to make this coupling less painful and more robust.