What tests do they run for fertility?

I have been TTC for over a year and I’m currently having very irregular cycles, even under the care of a gyno. When I go back to her at my next appointment, I want her to test for fertility- what if I don’t even have the ability to get pregnant? I want to know now as I am 31. I have never caught a positive OPK, although I admit I do it inconsistently due to my body skipping periods.

What tests do they typically run? Egg reserves? Follicles? I am pretty naive and do not really understand the standard tests, can anyone tell me from experience?

Thank you!