Require pair programming for a given set of exercises

lib/pair_programming23_study.rb

@@ -3,25 +3,27 @@
 class PairProgramming23Study
   ENABLE = ENV.fetch('PAIR_PROGRAMMING_23_STUDY', nil) == 'true'
   STUDY_GROUP_IDS = [368, 451].freeze
+  # All easy tasks of the first week to be solved by the participants on their own
+  EXCLUDED_EXERCISE_IDS = [636, 647, 648, 649, 637, 638, 623, 639, 650, 625, 624, 651, 653, 654, 655, 664, 656].freeze
+  # The participants are forced to work in pairs on these tasks
+  FORCED_EXERCISE_IDS = [723].freeze
 
   def self.participate?(user, exercise)
     ENABLE || participate_in_pp?(user, exercise)
   end
 
   def self.participate_in_pp?(user, exercise)
-    # All easy tasks of the first week to be solved by the participants on their own
-    if experiment_course?(user.current_study_group_id) && [636, 647, 648, 649, 637, 638, 623, 639, 650, 625, 624, 651, 653, 654, 655, 664, 656].exclude?(exercise.id)
-      return true if user.external_user? && fixed_enrolled_users.include?([user.consumer_id.to_s, user.external_id])
+    return false unless experiment_course?(user.current_study_group_id)
+    return false if EXCLUDED_EXERCISE_IDS.include?(exercise.id)
+    return true if user.external_user? && fixed_enrolled_users.include?([user.consumer_id.to_s, user.external_id])
 
-      user_group = user.id % 3 # => 0, 1, 2
-      case user_group
-        when 0, 1
-          return true
-        else # 2
-          return false
-      end
+    user_group = user.id % 3 # => 0, 1, 2
+    case user_group
+      when 0, 1
+        true
+      else # 2
+        false
     end
-    false
   end
 
   def self.experiment_course?(study_group_id)