Avoid costly Enum.count when matching against an empty list

Author: milmazz

test/scenic/primitives_test.exs

@@ -86,7 +86,7 @@ defmodule Scenic.PrimitivesTest do
       |> Graph.get!(:group)
 
     assert p.module == Scenic.Primitive.Group
-    assert Enum.count(p.data) == 0
+    assert p.data == []
     assert p.id == :group
   end