Add cucumber test for migrations

features/migration.feature

+Feature: Migration
+
+  Background:
+    Given I generate a new rails application
+    And I write to "app/models/user.rb" with:
+      """
+      class User < ActiveRecord::Base; end
+      """
+
+  Scenario: Vintage syntax
+    When I write to "db/migrate/01_add_attachment_to_users.rb" with:
+      """
+      class AddAttachmentToUsers < ActiveRecord::Migration
+        def self.up
+          create_table :users do |t|
+            t.has_attached_file :avatar
+          end
+        end
+
+        def self.down
+          drop_attached_file :users, :avatar
+        end
+      end
+      """
+    And I run a migration
+    Then I should have attachment columns for "avatar"
+
+    When I rollback a migration
+    Then I should not have attachment columns for "avatar"
+
+  Scenario: New syntax with create_table
+    When I write to "db/migrate/01_add_attachment_to_users.rb" with:
+      """
+      class AddAttachmentToUsers < ActiveRecord::Migration
+        def self.up
+          create_table :users do |t|
+            t.attachment :avatar
+          end
+        end
+      end
+      """
+    And I run a migration
+    Then I should have attachment columns for "avatar"
+
+  Scenario: New syntax outside of create_table
+    When I write to "db/migrate/01_create_users.rb" with:
+      """
+      class CreateUsers < ActiveRecord::Migration
+        def self.up
+          create_table :users
+        end
+      end
+      """
+    And I write to "db/migrate/02_add_attachment_to_users.rb" with:
+      """
+      class AddAttachmentToUsers < ActiveRecord::Migration
+        def self.up
+          add_attachment :users, :avatar
+        end
+
+        def self.down
+          remove_attachment :users, :avatar
+        end
+      end
+      """
+    And I run a migration
+    Then I should have attachment columns for "avatar"
+
+    When I rollback a migration
+    Then I should not have attachment columns for "avatar"

features/step_definitions/attachment_steps.rb

@@ -72,3 +72,31 @@ Then /^the attachment file "([^"]*)" should (not )?exist$/ do |filename, not_exi
     check_file_presence([attachment_path(filename)], !not_exist)
   end
 end
+
+Then /^I should have attachment columns for "([^"]*)"$/ do |attachment_name|
+  in_current_dir do
+    columns = eval(`bundle exec #{runner_command} "puts User.columns.map{ |column| [column.name, column.type] }.inspect"`.strip)
+    expect_columns = [
+      ["#{attachment_name}_file_name", :string],
+      ["#{attachment_name}_content_type", :string],
+      ["#{attachment_name}_file_size", :integer],
+      ["#{attachment_name}_updated_at", :datetime]
+    ]
+
+    expect_columns.all?{ |column| columns.include? column }.should be_true
+  end
+end
+
+Then /^I should not have attachment columns for "([^"]*)"$/ do |attachment_name|
+  in_current_dir do
+    columns = eval(`bundle exec #{runner_command} "puts User.columns.map{ |column| [column.name, column.type] }.inspect"`.strip)
+    expect_columns = [
+      ["#{attachment_name}_file_name", :string],
+      ["#{attachment_name}_content_type", :string],
+      ["#{attachment_name}_file_size", :integer],
+      ["#{attachment_name}_updated_at", :datetime]
+    ]
+
+    expect_columns.none?{ |column| columns.include? column }.should be_true
+  end
+end

features/step_definitions/rails_steps.rb

@@ -29,7 +29,11 @@ Given /^I run a paperclip generator to add a paperclip "([^"]*)" to the "([^"]*)
 end
 
 Given /^I run a migration$/ do
-  step %[I successfully run `bundle exec rake db:migrate`]
+  step %[I successfully run `bundle exec rake db:migrate --trace`]
+end
+
+When /^I rollback a migration$/ do
+  step %[I successfully run `bundle exec rake db:rollback STEPS=1 --trace`]
 end
 
 Given /^I update my new user view to include the file upload field$/ do