Prepare Python20 Course Experiments

lib/python20_course_week.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+class Python20CourseWeek
+
+  def self.get_for(exercise)
+    case exercise.title
+    when /Python20 Aufgabe 1/
+      1
+    when /Python20 Aufgabe 2/
+      2
+    when /Python20 Aufgabe 3/
+      3
+    when /Python20 Aufgabe 4/
+      4
+    when /Python20 Snake/
+      4
+    else
+      # Not part of the Python20 course
+      nil
+    end
+  end
+
+  def self.show_tips?(exercise, user_id)
+    week = get_for(exercise)
+    return true if week.nil? # Exercise is not part of the experiment
+
+    user_group = UserGroupSeparator.get_tips_group(user_id)
+    [1, 2].include?(week) && user_group == :show_tips
+  end
+
+  def self.show_linter?(exercise, user_id)
+    week = get_for(exercise)
+    return true if week.nil? # Exercise is not part of the experiment
+
+    user_group = UserGroupSeparator.get_linter_group(user_id)
+    [3].include?(week) && user_group == :show_linter
+  end
+end

lib/user_group_separator.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+class UserGroupSeparator
+
+  # Different user groups for Python20 course based on last digit of the user_id
+  # 0: show_tips && no_linter
+  # 1: no_tips && show_linter
+  # 2: show_tips && show_linter
+  # 3: no_tips && no_linter
+
+  # separates user into 50% no tips, 50% with tips
+  def self.get_tips_group(user_id)
+    user_group = user_id % 4 # => 0, 1, 2, 3
+    if [0, 2].include?(user_group)
+      :show_tips
+    else # [1, 3].include?(user_group)
+      :no_tips
+    end
+  end
+
+  # separates user into 50% with linter, 50% without linter
+  def self.get_linter_group(user_id)
+    user_group = user_id % 4 # => 0, 1, 2, 3
+    if [1, 2].include?(user_group)
+      :show_linter
+    else # [0, 3].include?(user_group)
+      :no_linter
+    end
+  end
+end