1 files changed, 9 insertions, 0 deletions
diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index c7245ab2db..3dae3916ff 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -994,6 +994,15 @@ class TestModule < Test::Unit::TestCase
     assert_equal([:bClass1], BClass.public_instance_methods(false))
   end
 
+  def test_undefined_instance_methods
+    assert_equal([],  AClass.undefined_instance_methods)
+    assert_equal([], BClass.undefined_instance_methods)
+    c = Class.new(AClass) {undef aClass}
+    assert_equal([:aClass], c.undefined_instance_methods)
+    c = Class.new(c)
+    assert_equal([], c.undefined_instance_methods)
+  end
+
   def test_s_public
     o = (c = Class.new(AClass)).new
     assert_raise(NoMethodError, /private method/) {o.aClass1}