Revert "Unused methods, module, etc."

This reverts commit 4e05bfb8e2.

Reason: BlankTopic#blank? should not be removed to check that dynamic finder with a bang can find a model that responds to `blank?`

activerecord/test/models/company_in_module.rb

@@ -71,6 +71,14 @@ module MyApplication
         i.belongs_to :nested_qualified_billing_firm, :class_name => 'MyApplication::Billing::Nested::Firm'
         i.belongs_to :nested_unqualified_billing_firm, :class_name => 'Nested::Firm'
       end
+
+      validate :check_empty_credit_limit
+
+      protected
+
+      def check_empty_credit_limit
+        errors.add_on_empty "credit_limit"
+      end
     end
   end
 end

activerecord/test/models/person.rb

@@ -91,6 +91,14 @@ class NestedPerson < ActiveRecord::Base
 
   has_one :best_friend, :class_name => 'NestedPerson', :foreign_key => :best_friend_id
   accepts_nested_attributes_for :best_friend, :update_only => true
+
+  def comments=(new_comments)
+    raise RuntimeError
+  end
+
+  def best_friend_first_name=(new_name)
+    assign_attributes({ :best_friend_attributes => { :first_name => new_name } })
+  end
 end
 
 class Insure

activerecord/test/models/task.rb

@@ -1,2 +1,5 @@
 class Task < ActiveRecord::Base
+  def updated_at
+    ending
+  end
 end

activerecord/test/models/topic.rb

@@ -26,6 +26,12 @@ class Topic < ActiveRecord::Base
     end
   }.new(self)
 
+  module NamedExtension
+    def two
+      2
+    end
+  end
+
   has_many :replies, :dependent => :destroy, :foreign_key => "parent_id"
   has_many :approved_replies, -> { approved }, class_name: 'Reply', foreign_key: "parent_id", counter_cache: 'replies_count'
   has_many :replies_with_primary_key, :class_name => "Reply", :dependent => :destroy, :primary_key => "title", :foreign_key => "parent_title"
@@ -102,6 +108,9 @@ class ImportantTopic < Topic
 end
 
 class BlankTopic < Topic
+  def blank?
+    true
+  end
 end
 
 module Web