Singleton classes returns parent's methods with instance_methods(false) and this makes remove_method in Module#delegate fail. Add a test case and fix the bug.

1 files changed, 14 insertions, 0 deletions

diff --git a/activesupport/test/core_ext/module_test.rb b/activesupport/test/core_ext/module_test.rb
index 9edd7cc7c0..1712b0649b 100644
--- a/activesupport/test/core_ext/module_test.rb
+++ b/activesupport/test/core_ext/module_test.rb
@@ -141,6 +141,20 @@ class ModuleTest < Test::Unit::TestCase
     assert_equal 0.0, nil_project.to_f
   end
 
+  def test_delegation_does_not_raise_error_when_removing_singleton_instance_methods
+    parent = Class.new do
+      def self.parent_method; end
+    end
+
+    assert_nothing_raised do
+      child = Class.new(parent) do
+        class << self
+          delegate :parent_method, :to => :superclass
+        end
+      end
+    end
+  end
+
   def test_parent
     assert_equal Yz::Zy, Yz::Zy::Cd.parent
     assert_equal Yz, Yz::Zy.parent