Merge pull request #16080 from opf/fix/fix-flaky-timeline-feature-spec

Fix flaky feature tests involving timeline

spec/support/pages/work_packages/work_packages_timeline.rb

@@ -83,6 +83,7 @@ def expect_timeline!(open: true)
       else
         expect(page).to have_no_css(".wp-table-timeline--container .wp-timeline-cell", visible: true)
       end
+      wait_for_network_idle
     end
 
     def timeline_row(wp_id)

spec/support/shared/cuprite_helpers.rb

@@ -36,6 +36,9 @@
 # being present or gone. Instead the execution is halted until
 # requested data is done being fetched.
 def wait_for_network_idle(...)
+  # `wait_for_network_idle` is available only when driver is Cuprite.
+  return unless page.driver.respond_to?(:wait_for_network_idle)
+
   page.driver.wait_for_network_idle(...)
 end