Update iteration title when dates change

Change autogenerated iterations default title to reflect any
changes in iteration dates.

ee/app/services/iterations/cadences/create_iterations_in_advance_service.rb

@@ -55,8 +55,7 @@ module Iterations
         # we end up having 2020-01-01(beginning of day) - 2020-01-07(end of day)
         start_date = next_start_date
         due_date = start_date + duration.weeks - 1.day
-        title = "Iteration #{iteration_number}: #{start_date.strftime(Date::DATE_FORMATS[:long])} - #{due_date.strftime(Date::DATE_FORMATS[:long])}"
-        description = "Auto-generated iteration for cadence##{cadence.id}: #{cadence.title} for period between #{start_date.strftime(Date::DATE_FORMATS[:long])} - #{due_date.strftime(Date::DATE_FORMATS[:long])}."
+        title = "Iteration #{iteration_number}: #{format_period(start_date, due_date)}"
 
         {
           iid: iid,
@@ -67,8 +66,7 @@ module Iterations
           start_date: start_date,
           due_date: due_date,
           state_enum: Iteration::STATE_ENUM_MAP[::Iteration.compute_state(start_date, due_date)],
-          title: title,
-          description: description
+          title: title
         }
       end
 
@@ -124,8 +122,11 @@ module Iterations
 
         existing_iterations_in_advance.each do |iteration|
           if iteration.duration_in_days != cadence.duration_in_days
+            old_title_dates_substring = format_period(iteration.start_date, iteration.due_date)
             iteration.start_date = prev_iteration.due_date + 1.day if prev_iteration
             iteration.due_date = iteration.start_date + cadence.duration_in_days.days - 1.day
+            new_title_dates_substring = format_period(iteration.start_date, iteration.due_date)
+            iteration.title = iteration.title.gsub(old_title_dates_substring, new_title_dates_substring)
           end
 
           prev_iteration = iteration
@@ -140,6 +141,12 @@ module Iterations
         end
       end
 
+      def format_period(start_date, due_date)
+        format = Date::DATE_FORMATS[:long]
+
+        "#{start_date.strftime(format)} - #{due_date.strftime(format)}"
+      end
+
       def compute_last_run_date
         reloaded_last_iteration = cadence_iterations.last
         run_date = reloaded_last_iteration.due_date - ((cadence.iterations_in_advance - 1) * cadence.duration_in_weeks).weeks if reloaded_last_iteration

ee/spec/services/iterations/cadences/create_iterations_in_advance_service_spec.rb

@@ -159,13 +159,13 @@ RSpec.describe Iterations::Cadences::CreateIterationsInAdvanceService do
                 expect(automated_cadence.reload.last_run_date).to eq(automated_cadence.reload.iterations.last(2).first.due_date)
               end
 
-              it 'sets the titles correctly based on iterations count and follow-up dates' do
+              it 'sets the title correctly based on iterations count and follow-up dates' do
                 subject
 
                 initial_start_date = past_iteration2.due_date + 1.day
                 initial_due_date = past_iteration2.due_date + 1.week
 
-                expect(group.reload.iterations.pluck(:title)).to eq([
+                expect(group.reload.iterations.due_date_order_asc.pluck(:title)).to eq([
                   'Iteration 1',
                   'Iteration 2',
                   "Iteration 3: #{(initial_start_date).strftime(Date::DATE_FORMATS[:long])} - #{initial_due_date.strftime(Date::DATE_FORMATS[:long])}",
@@ -174,6 +174,31 @@ RSpec.describe Iterations::Cadences::CreateIterationsInAdvanceService do
                 ])
               end
 
+              context 'when cadence changes duration' do
+                before do
+                  subject
+                  automated_cadence.update!(duration_in_weeks: 3)
+                  automated_cadence.reload
+                end
+
+                it 'adjusts iteration titles for iterations that are autogenerated and have the dates in the title' do
+                  subject
+                  # change duration and expect the titles for iterations containing dates in title to change
+                  described_class.new(user, automated_cadence).execute
+
+                  initial_start_date = past_iteration2.due_date + 1.day
+                  initial_due_date = past_iteration2.due_date + 1.week
+
+                  expect(group.reload.iterations.due_date_order_asc.pluck(:title)).to eq([
+                    'Iteration 1',
+                    'Iteration 2',
+                    "Iteration 3: #{(initial_start_date).strftime(Date::DATE_FORMATS[:long])} - #{initial_due_date.strftime(Date::DATE_FORMATS[:long])}",
+                    "Iteration 4: #{(initial_due_date + 1.day).strftime(Date::DATE_FORMATS[:long])} - #{(initial_due_date + 3.weeks).strftime(Date::DATE_FORMATS[:long])}",
+                    "Iteration 5: #{(initial_due_date + 3.weeks + 1.day).strftime(Date::DATE_FORMATS[:long])} - #{(initial_due_date + 6.weeks).strftime(Date::DATE_FORMATS[:long])}"
+                  ])
+                end
+              end
+
               it 'sets the states correctly based on iterations dates' do
                 subject