Adding docs

features/support/step_definitions/plate_steps.rb

@@ -129,12 +129,6 @@
   plate_purpose = PlatePurpose.find_by!(name: name)
   # binding.pry
   plate_purpose.create!(name: plate_name)
-
-  # Create requests for the wells of the plate
-  plate = Plate.find_by(name: plate_name)
-  plate.wells.each do |well|
-    FactoryBot.create(:customer_request, asset: well, sti_type: 'Request::LibraryCreation', state: 'pending')
-  end
 end
 
 Given(/^a plate called "([^"]*)" exists with purpose "([^"]*)"$/) do |name, purpose_name|

features/support/step_definitions/tag_layout_steps.rb

@@ -112,27 +112,45 @@ def check_tag2_layout(name, well_range, expected_wells_to_oligos) # rubocop:todo
   set_uuid_for(TagLayout.find(id).plate, uuid_value)
 end
 
+# Pooling from source plate ("Testing the API") to destination plate ("Testing the tagging") with a specified pooling
+# strategy
+#
 # rubocop:todo Metrics/MethodLength
 def pool_by_strategy(source, destination, pooling_strategy) # rubocop:todo Metrics/AbcSize
   unless pooling_strategy.sum == source.size
     Rails.logger.info("Pooling strategy does not fit plate size #{source.size}: #{pooling_strategy.inspect}")
   end
+
+  # Column major: reads columns from left to right, top to bottom
+  # Row major: reads rows from top to bottom, left to right
+  # For example, a 96-well plate would be read as: A1, B1, C1, D1, E1, F1, G1, H1, A2, B2, C2, D2, E2, F2, G2, H2, ...
   source_wells = source.wells.in_column_major_order.to_a
   destination_wells = destination.wells.in_column_major_order.to_a
 
   pooling_strategy.each_with_index do |pool, _old_submission_id|
+    # This will generate a new submission for each pool. So the number of submissions will be equal to the number of
+    # pools. For example, for a pooling strategy of [8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8], there will be 12 submissions.
     submission_id = Submission.create!(user: User.first || User.create!(login: 'a')).id
+    # Slice operation cuts the array in place (i.e., removes the elements cut from the well array),
+    # so we need to assign the result to a new variable
     wells_for_source, wells_for_destination = source_wells.slice!(0, pool), destination_wells.slice!(0, pool)
     wells_for_source
       .zip(wells_for_destination)
       .each do |w|
+        # Because of the way we use zip w.first would be the source, w.last would be the destination
+        # This is the transfer request that would be created by the API
         TransferRequest.create!(asset: w.first, target_asset: w.last, submission_id: submission_id)
         FactoryBot.create :request_without_submission,
                           asset: w.first,
                           target_asset: w.last,
                           submission_id: submission_id
       end
   end
+
+  # Create a request for each well in the destination plate
+  destination.wells.each do |well|
+    FactoryBot.create(:customer_request, asset: well, sti_type: 'Request::LibraryCreation', state: 'pending')
+  end
 end
 # rubocop:enable Metrics/MethodLength
 # This fakes out the transfers so that they look like they came from different submissions, effectively meaning