Ability Check

Is there a way to check whether a unit has an ability?
I have an ability which requires the unit to have a second ability (given to him when he casts an earlier copy of the spell) but as the spell is upgraded by engineering upgrade style ability, I may need to give it to him if he hasn't already got it, so I need to check whether the unit has the ability. If not then give it to him else do nothing sorta thing.

Check if the Level of the ability for (unit) is greater than 0, or not equal to 0.