Make system tests take failed screenshots in `before_teardown` hook

Previously we were calling the `take_failed_screenshot` method in an
`after_teardown` hook. However, this means that other teardown hooks
have to be executed before we take the screenshot. Since there can be
dynamic updates to the page after the assertion fails and before we
take a screenshot, it seems desirable to minimize that gap as much as
possible. Taking the screenshot in a `before_teardown` rather than an
`after_teardown` helps with that, and has a side benefit of allowing
us to remove the nested `ensure` commented on here:
https://github.com/rails/rails/pull/34411#discussion_r232819478

1 files changed, 7 insertions, 5 deletions

diff --git a/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb b/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb
index 600e9c733b..7080dbe022 100644
--- a/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb
+++ b/actionpack/lib/action_dispatch/system_testing/test_helpers/setup_and_teardown.rb
@@ -16,12 +16,14 @@ module ActionDispatch
           super
         end
 
+        def before_teardown
+          take_failed_screenshot
+        ensure
+          super
+        end
+
         def after_teardown
-          begin
-            take_failed_screenshot
-          ensure
-            Capybara.reset_sessions!
-          end
+          Capybara.reset_sessions!
         ensure
           super
         end