Move type-specific question code into subclasses

* Fixes Large Class smell
* Performed Replace Type Code With Subclasses refactoring
* Builds Question subclasses in QuestionsController

Author: jferris

example_app/app/controllers/questions_controller.rb

@@ -1,9 +1,10 @@
 class QuestionsController < ApplicationController
   def new
     @survey = Survey.find(params[:survey_id])
-    @question = @survey.questions.new
-    @question.options = [Option.new, Option.new, Option.new]
-    @question.type = params[:type]
+    build_question
+    if @question.type == 'MultipleChoiceQuestion'
+      @question.options = [Option.new, Option.new, Option.new]
+    end
   end
 
   def create
@@ -19,12 +20,14 @@ def create
   private
 
   def build_question
-    @question = @survey.questions.new(question_params, without_protection: true)
+    type = params[:question][:type]
+    @question = type.constantize.new(question_params)
+    @question.survey = @survey
   end
 
   def question_params
     params.
       require(:question).
-      permit(:type, :title, :options_attributes, :minimum, :maximum)
+      permit(:title, :options_attributes, :minimum, :maximum)
   end
 end

example_app/app/models/multiple_choice_question.rb

@@ -1,2 +1,15 @@
 class MultipleChoiceQuestion < Question
+  has_many :options, foreign_key: :question_id
+
+  accepts_nested_attributes_for :options, reject_if: :all_blank
+
+  def summary
+    total = answers.count
+    counts = answers.group(:text).order('COUNT(*) DESC').count
+    percents = counts.map do |text, count|
+      percent = (100.0 * count / total).round
+      "#{percent}% #{text}"
+    end
+    percents.join(', ')
+  end
 end

example_app/app/models/open_question.rb

@@ -1,2 +1,5 @@
 class OpenQuestion < Question
+  def summary
+    answers.order(:created_at).pluck(:text).join(', ')
+  end
 end

example_app/app/models/question.rb

@@ -3,53 +3,9 @@ class Question < ActiveRecord::Base
 
   QUESTION_TYPES = %w(OpenQuestion MultipleChoiceQuestion ScaleQuestion).freeze
 
-  validates :maximum, presence: true, if: :scale?
-  validates :minimum, presence: true, if: :scale?
   validates :type, presence: true, inclusion: QUESTION_TYPES
   validates :title, presence: true
 
   belongs_to :survey
   has_many :answers
-  has_many :options
-
-  accepts_nested_attributes_for :options, reject_if: :all_blank
-
-  def summary
-    case type
-    when 'MultipleChoiceQuestion'
-      summarize_multiple_choice_answers
-    when 'OpenQuestion'
-      summarize_open_answers
-    when 'ScaleQuestion'
-      summarize_scale_answers
-    end
-  end
-
-  def steps
-    (minimum..maximum).to_a
-  end
-
-  private
-
-  def scale?
-    type == 'ScaleQuestion'
-  end
-
-  def summarize_multiple_choice_answers
-    total = answers.count
-    counts = answers.group(:text).order('COUNT(*) DESC').count
-    percents = counts.map do |text, count|
-      percent = (100.0 * count / total).round
-      "#{percent}% #{text}"
-    end
-    percents.join(', ')
-  end
-
-  def summarize_open_answers
-    answers.order(:created_at).pluck(:text).join(', ')
-  end
-
-  def summarize_scale_answers
-    sprintf('Average: %.02f', answers.average('text'))
-  end
 end

example_app/app/models/scale_question.rb

@@ -1,2 +1,12 @@
 class ScaleQuestion < Question
+  validates :maximum, presence: true
+  validates :minimum, presence: true
+
+  def steps
+    (minimum..maximum).to_a
+  end
+
+  def summary
+    sprintf('Average: %.02f', answers.average('text'))
+  end
 end

example_app/app/views/questions/new.html.erb

@@ -1,4 +1,4 @@
-<%= simple_form_for @question, url: survey_questions_path(@survey) do |form| -%>
+<%= simple_form_for @question, as: :question, url: survey_questions_path(@survey) do |form| -%>
   <%= form.hidden_field :type %>
 
   <%= form.input :title %>
@@ -14,5 +14,5 @@
     <%= form.input :maximum %>
   <% end -%>
 
-  <%= form.submit %>
+  <%= form.submit 'Create Question' %>
 <% end -%>

example_app/app/views/surveys/show.html.erb

@@ -3,17 +3,17 @@
 
 <%= link_to(
   'Add Multiple Choice Question',
-  new_survey_question_path(@survey, type: 'MultipleChoiceQuestion')
+  new_survey_question_path(@survey, question: { type: 'MultipleChoiceQuestion' })
 ) %>
 
 <%= link_to(
   'Add Open Question',
-  new_survey_question_path(@survey, type: 'OpenQuestion')
+  new_survey_question_path(@survey, question: { type: 'OpenQuestion' })
 ) %>
 
 <%= link_to(
   'Add Scale Question',
-  new_survey_question_path(@survey, type: 'ScaleQuestion')
+  new_survey_question_path(@survey, question: { type: 'ScaleQuestion' })
 ) %>
 
 <%= simple_form_for [@survey, @completion] do |form| -%>

example_app/spec/factories/application.rb

@@ -15,12 +15,11 @@
     text 'Hello'
   end
 
-  factory :question do
+  factory :question, class: 'OpenQuestion' do
     survey
     title 'Question'
-    type 'OpenQuestion'
 
-    factory :multiple_choice_question do
+    factory :multiple_choice_question, class: 'MultipleChoiceQuestion' do
       ignore do
         options_texts { [] }
       end
@@ -30,16 +29,12 @@
           FactoryGirl.build(:option, text: text, question_id: attributes.id)
         end
       end
-
-      type 'MultipleChoiceQuestion'
     end
 
-    factory :open_question do
-      type 'OpenQuestion'
+    factory :open_question, class: 'OpenQuestion' do
     end
 
-    factory :scale_question do
-      type 'ScaleQuestion'
+    factory :scale_question, class: 'ScaleQuestion' do
     end
   end
 

example_app/spec/models/multiple_choice_question_spec.rb

@@ -0,0 +1,20 @@
+describe MultipleChoiceQuestion do
+  it { should have_many(:options) }
+end
+
+describe MultipleChoiceQuestion, '#summary' do
+  it 'returns a percentage breakdown' do
+    survey = create(:survey)
+    question = create(
+      :multiple_choice_question,
+      options_texts: %w(Blue Red),
+      survey: survey
+    )
+    taker = SurveyTaker.new(survey)
+    taker.answer question, 'Red'
+    taker.answer question, 'Blue'
+    taker.answer question, 'Red'
+
+    question.summary.should eq '67% Red, 33% Blue'
+  end
+end

example_app/spec/models/open_question_spec.rb

@@ -0,0 +1,13 @@
+describe OpenQuestion, '#summary' do
+  it 'returns all answers' do
+    survey = create(:survey)
+    question = create(:open_question, survey: survey)
+    taker = SurveyTaker.new(survey)
+
+    taker.answer question, 'Hey'
+    taker.answer question, 'Hi'
+    taker.answer question, 'Hello'
+
+    question.summary.should eq 'Hey, Hi, Hello'
+  end
+end