diff --git a/test/assert.rb b/test/assert.rb
index 121bd0a8e..a9bbc9a05 100644
--- a/test/assert.rb
+++ b/test/assert.rb
@@ -247,7 +247,7 @@ def pass
   assert_true(true)
 end
 
-def flunk(msg = nil, diff = "Epic Fail!")
+def flunk(msg = "Epic Fail!", diff = "")
   assert_true(false, msg, diff)
 end