There is no standard way of measuring dynamic range but it seems pretty easy in theory.
Just have a scene with a wide range of T-stops.
(I have no idea why so many test with F-stops)
There is testing equipment that goes up to 20 stops but the stops in the test have to line up with the stops in the camera which if you knew you would not need to do the test.
Next, the dynamic range of the lens has to match.
There is no true dynamic range test though there are so many people who claim that they know the true dynamic range and all of the camera companies are lying.