Add `allowing_for_delay` helper method for feature specs

cherry-picked

spec/features/profiles/preferences_spec.rb

@@ -21,10 +21,11 @@ describe 'Profile > Preferences' do
     it 'updates their preference' do
       choose "user_theme_id_#{theme.id}"
 
+      allowing_for_delay do
         visit page.current_path
-
         expect(page).to have_checked_field("user_theme_id_#{theme.id}")
       end
+    end
 
     it 'reflects the changes immediately' do
       expect(page).to have_selector("body.#{default.css_class}")
@@ -46,11 +47,12 @@ describe 'Profile > Preferences' do
     it 'updates their preference' do
       choose 'user_color_scheme_id_5'
 
+      allowing_for_delay do
         visit page.current_path
-
         expect(page).to have_checked_field('user_color_scheme_id_5')
       end
     end
+  end
 
   describe 'User changes their default dashboard' do
     it 'creates a flash message' do

spec/support/capybara.rb

@@ -19,3 +19,36 @@ unless ENV['CI'] || ENV['CI_SERVER']
   # Keep only the screenshots generated from the last failing test suite
   Capybara::Screenshot.prune_strategy = :keep_last_run
 end
+
+module CapybaraHelpers
+  # Execute a block a certain number of times before considering it a failure
+  #
+  # The given block is called, and if it raises a `Capybara::ExpectationNotMet`
+  # error, we wait `interval` seconds and then try again, until `retries` is
+  # met.
+  #
+  # This allows for better handling of timing-sensitive expectations in a
+  # sketchy CI environment, for example.
+  #
+  # interval - Delay between retries in seconds (default: 0.5)
+  # retries  - Number of times to execute before failing (default: 5)
+  def allowing_for_delay(interval: 0.5, retries: 5)
+    tries = 0
+
+    begin
+      yield
+    rescue Capybara::ExpectationNotMet => ex
+      if tries <= retries
+        tries += 1
+        sleep interval
+        retry
+      else
+        raise ex
+      end
+    end
+  end
+end
+
+RSpec.configure do |config|
+  config.include CapybaraHelpers, type: :feature
+end