Gearbox how to check after reassembly without putting back in the bike.

Can someone please tell me how I can check correctly that my 850 Norton Commando gearbox is working correctly with out putting it back into the bike. I have stripped it and put it back together but how do I know it is selecting the correct gears and that they are all working as they should. I know the cam plate is correct and positioned correctly and moves through 4th,3 2 neutral and first I just don't know if the gears are engaging correctly etc. Any advice would be greatly appreciated. The gearbox is on my bench and everything loosely put together. Thanks Pete.

The mainshaft should drive to the sleeve gear but at a different ratio for each and top will be 1:1.

Fit the gearbox sprocket and turn it as you change gears, the box will not select all gears when static, it has to be moving internally to give the dogs a chance to engage the mating gear.