An operation will trigger another thread to call an expected fn(). Is that possible that main thread wait until the expectation meet?

P.S. Apologies, I’m relatively new into testing and C++, so forgive me for any obvious mistakes.

Did anyone ever hear of a UT library that utilizes hooks to perform the mocks?

In CPP, gTest, version does not matter too much, I have a class that I would like to mock in order to use gMock. I therefore defined an interface and implement it once with the Mock class and once with something like a wrapper that just forwards the mocked methods to the original.

I have a scenario like below:

I am trying to mock std::make_shared