diff --git a/test/psych/test_yaml.rb b/test/psych/test_yaml.rb
index f1fa7f9c3d..45cd39d676 100644
--- a/test/psych/test_yaml.rb
+++ b/test/psych/test_yaml.rb
@@ -10,6 +10,9 @@ module Psych_Tests
 end
 
 class Psych_Unit_Tests < Psych::TestCase
+    def teardown
+        Psych.domain_types.clear
+    end
 	#
 	# Tests modified from 00basic.t in Psych.pm
 	#