Whirlpool QP, thermal fuse vs. door

Our DW gave up on us midcycle (power getting to unit, breaker is good, as this is hardwired I checked connections in the little metal box [junction box?] and everything is still connected (power off at the service box while this was done).

I would like to know if anyone would be able to tell me how to diagnose if it is the control on the doorlatch or the thermal fuse. I have an analog multimeter which has been calibrated. I watched the video on how to replace the thermal fuse, which looks super easy but I would like to know how to test the fuse before I buy a new one.

When I shut the door there is a click and it definitely latches firmly. How would I be able to test so I know which part to order?

Thank you, jlo