Requirements You need to have one of the php-xdebug or php-pcov extensions installed and enabled in order to capture coverage. If not available, PHPUnit execution will show you a warning about that ( "Warning: No code coverage driver available" ). Sanity check Run this command in moodle dir root: find . -name "*_test.php" | xargs grep -c @coversDefaultClas | grep -v ': [01] $' Verify that it reruns no occurrences. Running the tests with coverage enabled Init PHPUnit. For each of the test files modified in this issue (list of files at the end), run the following command: vendor/bin/phpunit -v --coverage-text path/to/test/file Verify the the test execution ends "ok". Verify that you get some textual output, with a summary a list of classes and some other information (details are not important). Important, verify that there isn't any warning or error about incorrect covers/coversclass annotations. List of files modified: lib/tests/http_client_test.php (only 402_STABLE and up) mod/quiz/tests/quiz_question_restore_test.php privacy/tests/legacy_polyfill_test.php question/bank/editquestion/tests/external/update_question_version_status_test.php