Easy , take few seeds place them in to warm dark place in to a moist paper towel with in 12-72 hours you should see some of them germinated... If not then they are probably not good....
I recently learned a new technique to tell if a seed is good. Gently press your thumb on it and it if pops it is no good because it was probably out of bud that was not cured correctly, if it does not pop it is good.