add comments to document mail job spec setup

spec/jobs/complete_registration_mail_job_spec.rb

@@ -3,6 +3,7 @@
 RSpec.describe CompleteRegistrationMailJob do
   let(:template) { :complete_registration }
 
+  # Must have confirmed email 4 weeks ago and not have completed registration
   let(:included) do
     create_list :user, 3, confirmed_at: 4.weeks.ago
   end

spec/jobs/continue_training_mail_job_spec.rb

@@ -16,6 +16,9 @@
   let(:included) { [user] }
   let(:excluded) { [user_2] }
 
+  # Must have started, but not completed training.
+  # Must be 4 weeks since their last visit
+  # `user_2` won't be included because they have a visit from 2 weeks ago
   before do
     create :visit,
            id: 9,
@@ -35,6 +38,7 @@
            user_id: user_2.id,
            started_at: 2.weeks.ago
 
+    # Travel to 4 weeks ago so that the module start event won't count as a recent visit
     travel_to 4.weeks.ago
     start_module(alpha)
     travel_back

spec/jobs/new_module_mail_job_spec.rb

@@ -4,20 +4,23 @@
   include_context 'with progress'
 
   let(:template) { :new_module }
-
+  
   let(:included) { [user] }
 
   let(:excluded) do
     create_list :user, 2, :registered, confirmed_at: 4.weeks.ago
   end
 
+  # Recipients must have completed all available modules - in this case, alpha and bravo
   before do
+    # Create records for the previously released modules completed by the recipients
+    # Each `module_release` must have a corresponding `release` record
     create(:release, id: 1)
     create(:module_release, release_id: 1, module_position: 1, name: 'alpha')
-
     create(:release, id: 2)
     create(:module_release, release_id: 1, module_position: 2, name: 'bravo')
 
+    # This will complete the alpha and bravo modules for `user`
     complete_module(alpha, 1.minute)
     complete_module(bravo, 1.minute)
   end

spec/jobs/start_training_mail_job_spec.rb

@@ -3,6 +3,7 @@
 RSpec.describe StartTrainingMailJob do
   let(:template) { :start_training }
 
+  # Must have confirmed email 4 weeks ago, completed registration and not have started training
   let(:included) do
     create_list :user, 3, :registered, confirmed_at: 4.weeks.ago
   end

spec/models/data/user_overview_spec.rb

@@ -75,16 +75,20 @@
 
   let(:release_1) { create(:release) }
 
-  # This is a mix of things and perhaps could be annotated
   before do
+    # create records for the previously released modules completed by the `new_module_mail_recipients`
     create(:module_release, release_id: release_1.id, module_position: 1, name: 'alpha')
     create(:module_release, release_id: release_1.id, module_position: 2, name: 'bravo')
     create(:module_release, release_id: release_1.id, module_position: 3, name: 'charlie')
+    # create notes for the `with_notes` and `without_notes` users
     create(:note, user: user_1)
     create(:note, user: user_2)
     create(:note, user: user_3)
+    # A user who has completed all available modules and will receive the new module mail
     create(:user, :registered, module_time_to_completion: { alpha: 2, charlie: 1, bravo: 3 })
+    # A user who confirmed their email 4 weeks ago will receive the complete registration mail
     create(:user, :confirmed, confirmed_at: 4.weeks.ago)
+    # A registered user who will receive the start training mail
     create(:user, :registered, confirmed_at: 4.weeks.ago)
   end