Yesterday I was at the "vechicle inspection". the car failed because the handbrake (manual) did not work on the right wheel. Is it possible to adjust only one side with the methode - foot brake down and pump the handbrake three times? Or how do I adjust one side? And how can I check that it was working?

Thank you,

It could be that the cable has snapped or an issue with the mechanism/caliper itself. 

To check that adjustments are working, you can jack the vehicle up and spin the wheel by hand, then check again after your adjustment and the wheel should be harder to spin or not spin at all.