Extract Decorator Step Eight

* Invert control

Author: jferris

example_app/app/controllers/summaries_controller.rb

@@ -1,11 +1,19 @@
 class SummariesController < ApplicationController
   def show
     @survey = Survey.find(params[:survey_id])
-    @summaries = @survey.summaries_using(summarizer, constraints)
+    @summaries = @survey.summaries_using(decorated_summarizer)
   end
 
   private
 
+  def decorated_summarizer
+    if include_unanswered?
+      summarizer
+    else
+      UnansweredQuestionHider.new(summarizer, current_user)
+    end
+  end
+
   def summarizer
     summarizer_class.new(user: current_user)
   end
@@ -14,14 +22,6 @@ def summarizer_class
     "Summarizer::#{params[:id].classify}".constantize
   end
 
-  def constraints
-    if include_unanswered?
-      {}
-    else
-      { answered_by: current_user }
-    end
-  end
-
   def include_unanswered?
     params[:unanswered]
   end

example_app/app/models/survey.rb

@@ -7,10 +7,9 @@ class Survey < ActiveRecord::Base
   has_many :completions
   has_many :questions
 
-  def summaries_using(summarizer, options = {})
+  def summaries_using(summarizer)
     questions.map do |question|
-      hider = UnansweredQuestionHider.new(summarizer, options[:answered_by])
-      question.summary_using(hider)
+      question.summary_using(summarizer)
     end
   end
 end

example_app/app/models/unanswered_question_hider.rb

@@ -17,6 +17,6 @@ def summarize(question)
   private
 
   def hide_unanswered_question?(question)
-    @user && !question.answered_by?(@user)
+    !question.answered_by?(@user)
   end
 end

example_app/spec/models/survey_spec.rb

@@ -20,32 +20,6 @@
     result.map(&:value).should == %w(result result)
   end
 
-  it 'applies the given summarizer to each question answered by the user' do
-    user = build_stubbed(:user)
-    answered_question = stub_question(user: user, answered: true)
-    unanswered_question = stub_question(user: user, answered: false)
-    questions = [answered_question, unanswered_question]
-    questions.stubs(:answered_by).with(user).returns(questions)
-    survey = build_stubbed(:survey, questions: questions)
-    summarizer = stub_summarizer
-
-    result = survey.summaries_using(summarizer, answered_by: user)
-
-    should_summarize_questions [answered_question], summarizer
-    result.map(&:title).should eq questions.map(&:title)
-    result.map(&:value).
-      should eq ['result', "You haven't answered this question"]
-  end
-
-  def stub_question(arguments)
-    build_stubbed(:question).tap do |question|
-      question.
-        stubs(:answered_by?).
-        with(arguments[:user]).
-        returns(arguments[:answered])
-    end
-  end
-
   def stub_summarizer
     stub('summarizer', summarize: 'result')
   end

example_app/spec/models/unanswered_question_hider_spec.rb

@@ -23,16 +23,6 @@
     result.should eq 'value'
   end
 
-  it 'delegates to the summarizer without a user' do
-    question = build_stubbed(:question)
-    summarizer = stub_summarizer(question, 'value')
-    hider = UnansweredQuestionHider.new(summarizer, nil)
-
-    result = hider.summarize(question)
-
-    result.should eq 'value'
-  end
-
   def stub_summarizer(question, value)
     stub('summarizer').tap do |summarizer|
       summarizer.stubs(:summarize).with(question).returns(value)