Use Paperclip sexy migration in the generator

lib/generators/paperclip/templates/paperclip_migration.rb.erb

 class <%= migration_class_name %> < ActiveRecord::Migration
   def self.up
+    change_table :<%= table_name %> do |t|
 <% attachment_names.each do |attachment| -%>
-    add_column :<%= name.underscore.camelize.tableize %>, :<%= attachment %>_file_name, :string
-    add_column :<%= name.underscore.camelize.tableize %>, :<%= attachment %>_content_type, :string
-    add_column :<%= name.underscore.camelize.tableize %>, :<%= attachment %>_file_size, :integer
-    add_column :<%= name.underscore.camelize.tableize %>, :<%= attachment %>_updated_at, :datetime
+      t.has_attached_file :<%= attachment %>
 <% end -%>
+    end
   end
 
   def self.down
 <% attachment_names.each do |attachment| -%>
-    remove_column :<%= name.underscore.camelize.tableize %>, :<%= attachment %>_file_name
-    remove_column :<%= name.underscore.camelize.tableize %>, :<%= attachment %>_content_type
-    remove_column :<%= name.underscore.camelize.tableize %>, :<%= attachment %>_file_size
-    remove_column :<%= name.underscore.camelize.tableize %>, :<%= attachment %>_updated_at
+    drop_attached_file :<%= table_name %>, :<%= attachment %>
 <% end -%>
   end
 end

test/generator_test.rb

@@ -18,17 +18,21 @@ class GeneratorTest < Rails::Generators::TestCase
           assert_match /class AddAttachmentAvatarToUsers/, migration
 
           assert_class_method :up, migration do |up|
-            assert_match /add_column :users, :avatar_file_name, :string/, up
-            assert_match /add_column :users, :avatar_content_type, :string/, up
-            assert_match /add_column :users, :avatar_file_size, :integer/, up
-            assert_match /add_column :users, :avatar_updated_at, :datetime/, up
+            expected = <<-migration
+              change_table :users do |t|
+                t.has_attached_file :avatar
+              end
+            migration
+
+            assert_equal expected.squish, up.squish
           end
 
           assert_class_method :down, migration do |down|
-            assert_match /remove_column :users, :avatar_file_name/, down
-            assert_match /remove_column :users, :avatar_content_type/, down
-            assert_match /remove_column :users, :avatar_file_size/, down
-            assert_match /remove_column :users, :avatar_updated_at/, down
+            expected = <<-migration
+              drop_attached_file :users, :avatar
+            migration
+
+            assert_equal expected.squish, down.squish
           end
         end
       end
@@ -44,25 +48,23 @@ class GeneratorTest < Rails::Generators::TestCase
           assert_match /class AddAttachmentAvatarPhotoToUsers/, migration
 
           assert_class_method :up, migration do |up|
-            assert_match /add_column :users, :avatar_file_name, :string/, up
-            assert_match /add_column :users, :avatar_content_type, :string/, up
-            assert_match /add_column :users, :avatar_file_size, :integer/, up
-            assert_match /add_column :users, :avatar_updated_at, :datetime/, up
-            assert_match /add_column :users, :photo_file_name, :string/, up
-            assert_match /add_column :users, :photo_content_type, :string/, up
-            assert_match /add_column :users, :photo_file_size, :integer/, up
-            assert_match /add_column :users, :photo_updated_at, :datetime/, up
+            expected = <<-migration
+              change_table :users do |t|
+                t.has_attached_file :avatar
+                t.has_attached_file :photo
+              end
+            migration
+
+            assert_equal expected.squish, up.squish
           end
 
           assert_class_method :down, migration do |down|
-            assert_match /remove_column :users, :avatar_file_name/, down
-            assert_match /remove_column :users, :avatar_content_type/, down
-            assert_match /remove_column :users, :avatar_file_size/, down
-            assert_match /remove_column :users, :avatar_updated_at/, down
-            assert_match /remove_column :users, :photo_file_name/, down
-            assert_match /remove_column :users, :photo_content_type/, down
-            assert_match /remove_column :users, :photo_file_size/, down
-            assert_match /remove_column :users, :photo_updated_at/, down
+            expected = <<-migration
+              drop_attached_file :users, :avatar
+              drop_attached_file :users, :photo
+            migration
+
+            assert_equal expected.squish, down.squish
           end
         end
       end