Run the following, confirm there are no files listed:
$ git grep -l "^class lib_test" | xargs grep --files-without-match '^namespace'
Confirm the following tests pass:
$ vendor/bin/phpunit mod/h5pactivity/tests/lib_test.php
All tests should ideally be in the namespace of the component/class they are testing - especially in the case of generic lib_test classes (of which there are a few across different components)