In reply to Rana Adeel Ahmad:
You can get FSM state and transtion coverage for your state machine by just turning on code coverage in your simulator. Then you just generate a coverage report as your evidence.
I would want my test plan to state that the design must have 100% state coverage and also 100% transition coverage
You can also generate functional coverage to verify specific transition paths through the FSM. some examples of that are mentioned here:
If you wanted the additional functional coverage, then I would expect that the test plan would state that the coverpoint/covergroups used for the FSM transition path coverage should be at 100%
How you capture that test plan will most likely be vendor specific