Split nil to empty array

Author: fahchen

lib/ltree.ex

@@ -57,6 +57,7 @@ defmodule Hierarch.LTree do
   @doc """
   Split string path into an arry
   """
+  def split(nil), do: []
   def split(""), do: []
   def split(path) when is_binary(path) do
     String.split(path, @separator)

test/ltree_test.exs

@@ -42,4 +42,12 @@ defmodule Hierarch.LtreeTest do
       assert root_id == "Top"
     end
   end
+
+  describe "split/1" do
+    test "works" do
+      assert [] == LTree.split(nil)
+      assert [] == LTree.split("")
+      assert ["Top", "Science"] == LTree.split("Top.Science")
+    end
+  end
 end