Cap teacher response rate at 100 percent

app/models/response_rate.rb

@@ -6,27 +6,32 @@ class ResponseRate
   end
 
   def student
-    return 0 unless student_survey_item_count.positive?
+    rate(survey_item_count: student_survey_item_count, response_count: student_response_count,
+         total_possible_responses: total_possible_student_responses)
+  end
 
-    average_responses_per_survey_item = student_response_count / student_survey_item_count
+  def teacher
+    response_rate = rate(survey_item_count: teacher_survey_item_count, response_count: teacher_response_count,
+                         total_possible_responses: total_possible_teacher_responses)
+    cap_at_100(response_rate)
+  end
 
-    return 0 unless total_possible_student_responses.positive?
+  private
 
-    (average_responses_per_survey_item / total_possible_student_responses * 100).round
+  def cap_at_100(response_rate)
+    response_rate > 100 ? 100 : response_rate
   end
 
-  def teacher
-    return 0 unless teacher_survey_item_count.positive?
+  def rate(survey_item_count:, response_count:, total_possible_responses:)
+    return 0 unless survey_item_count.positive?
 
-    average_responses_per_survey_item = teacher_response_count / teacher_survey_item_count
+    average_responses_per_survey_item = response_count / survey_item_count
 
-    return 0 unless total_possible_teacher_responses.positive?
+    return 0 unless total_possible_responses.positive?
 
-    (average_responses_per_survey_item / total_possible_teacher_responses * 100).round
+    (average_responses_per_survey_item / total_possible_responses * 100).round
   end
 
-  private
-
   def total_possible_student_responses
     @total_possible_student_responses ||= total_possible_responses do |responses|
       responses.total_students

spec/models/response_rate_spec.rb

@@ -67,12 +67,13 @@ describe ResponseRate, type: :model do
                   survey_item: insufficient_student_survey_item, academic_year: ay, school: school, likert_score: 1)
     end
 
-    context 'when the average number of teacher responses per question in a subcategory is equal to the teacher response threshold' do
+    context 'when the average number of teacher responses per question in a subcategory is equal to the total possible responses' do
       it 'returns 100 percent' do
         expect(ResponseRate.new(subcategory: subcategory, school: school,
                                 academic_year: ay).teacher).to eq 100
       end
     end
+
     context 'when the average number of teacher responses is 77.9, the response rate averages up to 78 percent' do
       before do
         create_list(:survey_item_response, 2, survey_item: sufficient_teacher_survey_item_3,
@@ -83,5 +84,16 @@ describe ResponseRate, type: :model do
                                 academic_year: ay).teacher).to eq 78
       end
     end
+
+    context 'when the average number of teacher responses is greater than the total possible responses' do
+      before do
+        create_list(:survey_item_response, SurveyItemResponse::TEACHER_RESPONSE_THRESHOLD + 1, survey_item: sufficient_teacher_survey_item_3,
+                                                                                               academic_year: ay, school: school, likert_score: 1)
+      end
+      it 'returns 100 percent' do
+        expect(ResponseRate.new(subcategory: subcategory, school: school,
+                                academic_year: ay).teacher).to eq 100
+      end
+    end
   end
 end