Run test: ./vendor/bin/phpunit --filter test_validate_deprecated_strings_files Edit lang/en/deprecate.txt and replace its contents: mybackpack ,core_badges mybadges, core_badges myfiles , core myfilesmanage,core, mypreferences,core_grades ,myprofile,core viewallmyentries,core_blog,Placeholder cannotdeleteposts,core_notes addedotag,core_tags newname,core_tag (Note the final entry has trailing whitespace) Run the test again Confirm 8 failures - the leading and trailing whitespace do not cause failures