Replace Subclasses with Strategies: Step Seven

* Convert strategies to ActiveRecord subclasses
* Create empty tables for strategies

Author: jferris

example_app/app/models/multiple_choice_submittable.rb

@@ -1,7 +1,5 @@
-class MultipleChoiceSubmittable
-  def initialize(question)
-    @question = question
-  end
+class MultipleChoiceSubmittable < ActiveRecord::Base
+  has_one :question, as: :submittable
 
   def breakdown
     total = answers.count
@@ -28,10 +26,10 @@ def score(text)
   private
 
   def answers
-    @question.answers
+    question.answers
   end
 
   def options
-    @question.options
+    question.options
   end
 end

example_app/app/models/open_submittable.rb

@@ -1,7 +1,5 @@
-class OpenSubmittable
-  def initialize(question)
-    @question = question
-  end
+class OpenSubmittable < ActiveRecord::Base
+  has_one :question, as: :submittable
 
   def breakdown
     text_from_ordered_answers = answers.order(:created_at).pluck(:text)
@@ -15,6 +13,6 @@ def score(text)
   private
 
   def answers
-    @question.answers
+    question.answers
   end
 end

example_app/app/models/question.rb

@@ -17,8 +17,8 @@ def most_recent_answer_text
   end
 
   def submittable
-    submittable_class_name = type.sub('Question', 'Submittable')
-    submittable_class_name.constantize.new(self)
+    submittable_class = type.sub('Question', 'Submittable').constantize
+    submittable_class.new(question: self)
   end
 
   def summarize(summarizer)
@@ -28,7 +28,8 @@ def summarize(summarizer)
 
   def switch_to(type, new_attributes)
     attributes = self.attributes.merge(new_attributes)
-    new_question = type.constantize.new(attributes.except('id', 'type'))
+    cloned_attributes = attributes.except('id', 'type', 'submittable_type')
+    new_question = type.constantize.new(cloned_attributes)
     new_question.id = id
 
     begin

example_app/app/models/scale_submittable.rb

@@ -1,7 +1,5 @@
-class ScaleSubmittable
-  def initialize(question)
-    @question = question
-  end
+class ScaleSubmittable < ActiveRecord::Base
+  has_one :question, as: :submittable
 
   def breakdown
     sprintf('Average: %.02f', answers.average('text'))
@@ -12,12 +10,12 @@ def score(text)
   end
 
   def steps
-    (@question.minimum..@question.maximum).to_a
+    (question.minimum..question.maximum).to_a
   end
 
   private
 
   def answers
-    @question.answers
+    question.answers
   end
 end

example_app/db/migrate/20130131205117_create_multiple_choice_submittables.rb

@@ -0,0 +1,7 @@
+class CreateMultipleChoiceSubmittables < ActiveRecord::Migration
+  def change
+    create_table :multiple_choice_submittables do |table|
+      table.timestamps null: false
+    end
+  end
+end

example_app/db/migrate/20130131205432_create_open_submittables.rb

@@ -0,0 +1,7 @@
+class CreateOpenSubmittables < ActiveRecord::Migration
+  def change
+    create_table :open_submittables do |table|
+      table.timestamps null: false
+    end
+  end
+end

example_app/db/migrate/20130131205918_create_scale_submittables.rb

@@ -0,0 +1,7 @@
+class CreateScaleSubmittables < ActiveRecord::Migration
+  def change
+    create_table :scale_submittables do |table|
+      table.timestamps null: false
+    end
+  end
+end

example_app/db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20130116211337) do
+ActiveRecord::Schema.define(:version => 20130131205918) do
 
   create_table "answers", :force => true do |t|
     t.integer  "completion_id", :null => false
@@ -48,6 +48,16 @@
   add_index "invitations", ["survey_id"], :name => "index_invitations_on_survey_id"
   add_index "invitations", ["token"], :name => "index_invitations_on_token", :unique => true
 
+  create_table "multiple_choice_submittables", :force => true do |t|
+    t.datetime "created_at", :null => false
+    t.datetime "updated_at", :null => false
+  end
+
+  create_table "open_submittables", :force => true do |t|
+    t.datetime "created_at", :null => false
+    t.datetime "updated_at", :null => false
+  end
+
   create_table "options", :force => true do |t|
     t.integer  "question_id",                :null => false
     t.string   "text",                       :null => false
@@ -66,6 +76,11 @@
     t.integer  "maximum"
   end
 
+  create_table "scale_submittables", :force => true do |t|
+    t.datetime "created_at", :null => false
+    t.datetime "updated_at", :null => false
+  end
+
   create_table "surveys", :force => true do |t|
     t.string   "title",      :null => false
     t.datetime "created_at", :null => false

example_app/spec/models/multiple_choice_submittable_spec.rb

@@ -1,3 +1,7 @@
+describe MultipleChoiceSubmittable do
+  it { should have_one(:question) }
+end
+
 describe MultipleChoiceSubmittable, '#breakdown' do
   it 'returns a percentage breakdown' do
     survey = create(:survey)
@@ -6,7 +10,7 @@
       options_texts: %w(Blue Red),
       survey: survey
     )
-    submittable = MultipleChoiceSubmittable.new(question)
+    submittable = MultipleChoiceSubmittable.new(question: question)
     taker = AnswerCreator.new(survey)
     taker.answer question, 'Red'
     taker.answer question, 'Blue'
@@ -19,22 +23,22 @@
 describe MultipleChoiceSubmittable, '#options_for_form' do
   it 'adds empty options when none are present' do
     question = build_stubbed(:multiple_choice_question, options: [])
-    submittable = MultipleChoiceSubmittable.new(question)
+    submittable = MultipleChoiceSubmittable.new(question: question)
     submittable.options_for_form.count.should == 3
   end
 
   it 'leaves existing options alone' do
     options = [Option.new(text: 'hey'), Option.new(text: 'hello')]
     question = build_stubbed(:multiple_choice_question, options: options)
-    submittable = MultipleChoiceSubmittable.new(question)
+    submittable = MultipleChoiceSubmittable.new(question: question)
     submittable.options_for_form.map(&:text).should match_array(['hey', 'hello'])
   end
 end
 
 describe MultipleChoiceSubmittable, '#score' do
   it 'returns the score for the option with the given text' do
     question = build_stubbed(:multiple_choice_question)
-    submittable = MultipleChoiceSubmittable.new(question)
+    submittable = MultipleChoiceSubmittable.new(question: question)
     question.options.target.stubs(score: 2)
 
     result = submittable.score('two')

example_app/spec/models/open_submittable_spec.rb

@@ -1,8 +1,12 @@
+describe OpenSubmittable do
+  it { should have_one(:question) }
+end
+
 describe OpenSubmittable, '#breakdown' do
   it 'returns all answers' do
     survey = create(:survey)
     question = create(:open_question, survey: survey)
-    submittable = OpenSubmittable.new(question)
+    submittable = OpenSubmittable.new(question: question)
     taker = AnswerCreator.new(survey)
 
     taker.answer question, 'Hey'
@@ -16,7 +20,7 @@
 describe OpenSubmittable, '#score' do
   it 'returns zero' do
     question = build_stubbed(:open_question)
-    submittable = OpenSubmittable.new(question)
+    submittable = OpenSubmittable.new(question: question)
 
     result = submittable.score('anything')