add a test for adding normal function
add a test for adding normal function

chainer/chainer,keisuke-umezawa/chainer,jnishi/chainer,wkentaro/chainer,cupy/cupy,pfnet/chainer,jnishi/chainer,jnishi/chainer,tkerola/chainer,ktnyt/chainer,cupy/cupy,wkentaro/chainer,hvy/chainer,niboshi/chainer,keisuke-umezawa/chainer,rezoo/chainer,kashif/chainer,niboshi/chainer,ktnyt/chainer,jnishi/chainer,okuta/chainer,okuta/chainer,niboshi/chainer,ysekky/chainer,ronekko/chainer,delta2323/chainer,hvy/chainer,hvy/chainer,keisuke-umezawa/chainer,cupy/cupy,niboshi/chainer,ktnyt/chainer,cupy/cupy,anaruse/chainer,ktnyt/chainer,chainer/chainer,chainer/chainer,hvy/chainer,keisuke-umezawa/chainer,chainer/chainer,kiyukuta/chainer,aonotas/chainer,okuta/chainer,wkentaro/chainer,wkentaro/chainer,okuta/chainer