To test: Create a new numerical question. Text doesn't matter. Set the answer, for instance, to 1E-6, and accepted error to 5E-7, 100% grade. Save the question. TEST: Re-edit it: the answer should be shown as originally set (1E-6) or some numerically equivalent expression. TEST: Run the DB unit tests (Admin->Development->Functional DB tests) against all the DB drivers (mysqli, pgsql, mssql, sqlsrv and oci). No failures/exception should happen in the test_insert_record, test_update_record and test_set_field unit tests. Note: At the time of writing these instructions all the DB drivers but the sqlsrv one have been already tested. Also it would be interesting to run it in one 32bits LAMP stack (I've 64bits here only).