diff --git a/test/tc_util.rb b/test/tc_util.rb
index 9e03423..345bb51 100644
--- a/test/tc_util.rb
+++ b/test/tc_util.rb
@@ -11,6 +11,19 @@
 
 class TestUtil < Test::Unit::TestCase
 
+  def test_clean_json
+    json_ok = { :one => "one", :uri => URI.parse("/file.txt") }
+    json_nil = { :nil => nil }
+    json_empty = { :empty => "" }
+    json_mix = json_ok.merge(json_nil).merge(json_empty)
+    empty = {}
+
+    assert_same json_ok, ROBundle::Util.clean_json(json_ok)
+    assert_equal empty, ROBundle::Util.clean_json(json_nil)
+    assert_equal empty, ROBundle::Util.clean_json(json_empty)
+    assert_equal json_ok, ROBundle::Util.clean_json(json_mix)
+  end
+
   def test_parse_time
     now = Time.now
     iso = now.iso8601