Replace Subclasses with Strategies: Step One

* Extract one method to a strategy for each subclass

example_app/app/models/multiple_choice_question.rb

@@ -12,7 +12,7 @@ def options_for_form
   end
 
   def score(text)
-    options.score(text)
+    submittable.score(text)
   end
 
   def breakdown
@@ -24,4 +24,8 @@ def breakdown
     end
     percents.join(', ')
   end
+
+  def submittable
+    MultipleChoiceSubmittable.new(self)
+  end
 end

example_app/app/models/multiple_choice_submittable.rb

@@ -0,0 +1,15 @@
+class MultipleChoiceSubmittable
+  def initialize(question)
+    @question = question
+  end
+
+  def score(text)
+    options.score(text)
+  end
+
+  private
+
+  def options
+    @question.options
+  end
+end

example_app/app/models/open_question.rb

@@ -1,10 +1,14 @@
 class OpenQuestion < Question
   def score(text)
-    0
+    submittable.score(text)
   end
 
   def breakdown
     text_from_ordered_answers = answers.order(:created_at).pluck(:text)
     text_from_ordered_answers.join(', ')
   end
+
+  def submittable
+    OpenSubmittable.new
+  end
 end

example_app/app/models/open_submittable.rb

@@ -0,0 +1,5 @@
+class OpenSubmittable
+  def score(text)
+    0
+  end
+end

example_app/app/models/scale_question.rb

@@ -3,7 +3,7 @@ class ScaleQuestion < Question
   validates :minimum, presence: true
 
   def score(text)
-    text.to_i
+    submittable.score(text)
   end
 
   def steps
@@ -13,4 +13,8 @@ def steps
   def breakdown
     sprintf('Average: %.02f', answers.average('text'))
   end
+
+  def submittable
+    ScaleSubmittable.new
+  end
 end

example_app/app/models/scale_submittable.rb

@@ -0,0 +1,5 @@
+class ScaleSubmittable
+  def score(text)
+    text.to_i
+  end
+end

example_app/spec/models/multiple_choice_submittable_spec.rb

@@ -0,0 +1,12 @@
+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)
+    question.options.target.stubs(score: 2)
+
+    result = submittable.score('two')
+
+    question.options.target.should have_received(:score).with('two')
+    result.should eq 2
+  end
+end

example_app/spec/models/open_submittable_spec.rb

@@ -0,0 +1,9 @@
+describe OpenSubmittable, '#score' do
+  it 'returns zero' do
+    submittable = OpenSubmittable.new
+
+    result = submittable.score('anything')
+
+    result.should eq 0
+  end
+end

example_app/spec/models/scale_submittable_spec.rb

@@ -0,0 +1,9 @@
+describe ScaleSubmittable, '#score' do
+  it 'returns the integer value of the text' do
+    submittable = ScaleSubmittable.new
+
+    result = submittable.score('5')
+
+    result.should eq 5
+  end
+end