Fix flickering split screen spec by waiting for the relation tab to be loaded before checking for missing elements.

Author: dombesz

Diff for: spec/support/components/work_packages/relations.rb

@@ -56,11 +56,18 @@ def find_relatable(relatable)
         end
       end
 
+      def expect_tab_is_loaded
+        within("wp-relations-tab") do
+          expect(page).to have_no_css("op-content-loader")
+        end
+      end
+
       def expect_add_relation_button
         expect(page).to have_test_selector("new-relation-action-menu")
       end
 
       def expect_no_add_relation_button
+        expect_tab_is_loaded # Make sure the tab is loaded before checking non existing elements
         expect(page).not_to have_test_selector("new-relation-action-menu")
       end
 
@@ -83,6 +90,7 @@ def expect_row(work_package)
       end
 
       def expect_no_row(relatable)
+        expect_tab_is_loaded # Make sure the tab is loaded before checking non existing elements
         actual_relatable = find_relatable(relatable)
         expect(page).not_to have_test_selector("op-relation-row-visible-#{actual_relatable.id}"),
                             "expected no relation row for work package " \
@@ -303,6 +311,7 @@ def expect_parent(work_package)
       end
 
       def expect_no_parent
+        expect_tab_is_loaded # Make sure the tab is loaded before checking non existing elements
         expect(page).not_to have_test_selector "op-wp-breadcrumb-parent", wait: 10
       end