Unit Test for function with mat paginator method firstPage()

I have a function I am trying to test. I am using the matPaginator.firstPage() method inside of it. However any test I write for this function I can an error of

"Cannot read property 'firstPage' of undefined"

I cannot find anything on how to mock paginator in unit tests or provided it in my spec file that will allow this test to complete.

Any help/suggestions/tips would be much appreciated.

from Unit Test for function with mat paginator method firstPage()