Zanussi ZJD1219 Washer/Dryer has fault E10?

Zanussi ZJD1219 Washer/Dryer has fault E10

I understand that E10 means that the water inflow solenoids are faulty (specifically the one to the tumble dryer in my case).

If i try to repair this and order the new solenoid part how can i be sure that it will solve the problem i.e can i test that the original solenoid is faulty somehow before purchasing another?

Any advise will be grately received.