func randVName(v *spb.VName, size int) {
v.Signature = testutil.RandStr(size)
v.Corpus = testutil.RandStr(size)
v.Root = testutil.RandStr(size)
v.Path = testutil.RandStr(size)
v.Language = testutil.RandStr(size)
}
func randUpdate(u *spb.WriteRequest_Update, size int) {
u.Target = &spb.VName{}
randVName(u.GetTarget(), size)
u.EdgeKind = testutil.RandStr(2)
u.FactName = testutil.RandStr(size)
u.FactValue = factValue
}