Document and add spec for delegating to constants in Forwardable

Fixes [Bug #13142]

1 files changed, 11 insertions, 0 deletions

diff --git a/test/test_forwardable.rb b/test/test_forwardable.rb
index b3f8467c5c..0a90d3a878 100644
--- a/test/test_forwardable.rb
+++ b/test/test_forwardable.rb
@@ -3,6 +3,7 @@ require 'test/unit'
 require 'forwardable'
 
 class TestForwardable < Test::Unit::TestCase
+  INTEGER = 42
   RECEIVER = BasicObject.new
   RETURNED1 = BasicObject.new
   RETURNED2 = BasicObject.new
@@ -27,6 +28,16 @@ class TestForwardable < Test::Unit::TestCase
     end
   end
 
+  def test_def_instance_delegator_constant
+    %i[def_delegator def_instance_delegator].each do |m|
+      cls = forwardable_class do
+        __send__ m, 'TestForwardable::INTEGER', :to_i
+      end
+
+      assert_equal 42, cls.new.to_i
+    end
+  end
+
   def test_def_instance_delegator_using_args_method_as_receiver
     %i[def_delegator def_instance_delegator].each do |m|
       cls = forwardable_class(