Add a test for delegating a method ending in '=' as this is a special case.

activesupport/lib/active_support/core_ext/module/delegation.rb

@@ -1,4 +1,5 @@
 require 'active_support/core_ext/object/public_send'
+
 class Module
   # Provides a delegate class method to easily expose contained objects' methods
   # as your own. Pass one or more methods (specified as symbols or strings)

activesupport/test/core_ext/module_test.rb

@@ -27,6 +27,8 @@ module Yz
 end
 
 Somewhere = Struct.new(:street, :city) do
+  attr_accessor :name
+
   protected
 
   def protected_method
@@ -40,6 +42,7 @@ end
 
 class Someone < Struct.new(:name, :place)
   delegate :street, :city, :to_f, :protected_method, :private_method, :to => :place
+  delegate :name=, :to => :place, :prefix => true
   delegate :upcase, :to => "place.city"
 
   FAILED_DELEGATE_LINE = __LINE__ + 1
@@ -85,6 +88,11 @@ class ModuleTest < Test::Unit::TestCase
     assert_equal "Chicago", @david.city
   end
 
+  def test_delegation_to_assignment_method
+    @david.place_name = "Fred"
+    assert_equal "Fred", @david.place.name
+  end
+
   def test_delegation_to_protected_method
     assert_raise(NoMethodError) { @david.protected_method }
   end