Solved. Very tricky problem . The issue is coming not from the fact that the UnsupportedOperationException is runtime exception, but because the exception is thrown one layer higher that the real mocked interface and so the mock reports a missing call.
Nice to see that you already resolved the problem.
BTW, you can remove the try-catch construct around setting up your mockserver and instead simply declare your test to throw the exception.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
You showed up just in time for the waffles! And this tiny ad:
Building a Better World in your Backyard by Paul Wheaton and Shawn Klassen-Koop