I´m not sure about a test, but I really notice it when doing intervals. For example; towards the end of a phase of Zone 4 workouts, I cannot produce enough ‘power’ to get my heart rate into Zone 4. I think that this is my muscular endurance (legs) limiting my ability as opposed to my heart, as my heart/lungs don’t feel taxed.
Unfortunately this isn’t a ‘test’, but the result of experience.
J.