handle nil return (#18)

lib/cache/term_encoder.ex

@@ -62,6 +62,7 @@ defmodule Cache.TermEncoder do
  value
  end
 
+ def decode_json(nil), do: nil
  def decode_json(json) do
  case Jason.decode(json) do
  {:ok, data} -> data

test/cache/redis_json_test.exs

@@ -37,6 +37,10 @@ defmodule Cache.RedisJSONTest do
  "some_map" => %{"one" => 1, "two" => 2, "three" => 3, "four" => 4}
  }} === RedisCache.json_get(key)
  end
+
+ test "returns :ok and nil if key not found" do
+ assert {:ok, nil} === RedisCache.json_get("non_existing")
+ end
  end
 
  describe "&json_get/2" do