Undefined constant "DRUPAL_TEST_IN_CHILD_SITE"

I also see this issue every time I am installing a site with this module on it. I can fix this by running a database-import. I think we can redefine the const in the module or put an `if (!defined()` guard around it.

I've added the fix. However, tests are not covering all types of errors, such as user and notices. It would be good if who's gonna review this is able to manually test all possible scenarios. You can use the testing module to simulate errors. It's easy to run the site now:

ddev start
ddev poser
ddev symlink-project
ddev install

Do some changes to templates and go and visit the pages from error_page_test.routing.yml

This bug was cause by the fact that we are forking in this module the core/includes/errors.inc file. I've discovered that the file has diverged. I've added a test in this MR (see .gitlab-ci.yml) that detects if the core's file will change, so that we can adapt our code.

Please refer to #6 🐛 Undefined constant "DRUPAL_TEST_IN_CHILD_SITE" Active for testing the changes.

Thank you for reporting

Automatically closed - issue fixed for 2 weeks with no activity.