Very hard to check stationary mate.

Helical LSD's dont work without a specific load. Or no load.

Helical LSD's work as a normal diff on light load driving. On a front wheel drive they have to.
If they lock up while turning, youll get understeer like no tomorrow.

To be honest mate. This isnt the right way of doing it. But get soapy water. Splash it under your front wheels. Pull the handbrake. And spin the wheels for a few seconds while someone observes both wheels.

If both turn. Its working. If one turns. You got a problem. Or its not getting enough load.

Really. Technically speaking. If there is no drive to one side, you wont be moving at all. Itll be like snapping a driveshaft with a normal diff. There will be no drive at all.