Weak form of Electric field , test(pzd.EX)

Hey all

I am working in the 2D piezoelectric module and I want to take weak forms of
Electric field in different direction, test(pzd.EX) and test(pzd.EY) but its showing error.

When I try by making the electric field unit less, like test(pzd.EX/1[m/V]) and test(pzd.EY/1[m/V]) ,its working
but I am not sure if its correct way.May be test function only takes numerical values only



Any idea will be of great help. Its has almost stopped my work.


Thank you