Debug build of Firebird sends the real auth errors to client in addition to logging it into firebird.log. Because of this the test's output is not as expected. It is a false negative.
> assert act.clean_stdout == act.clean_expected_stdout
E assert
E Statement failed, SQLSTATE = 08006
E Error occurred during login, please check server firebird.log for details
E + -file is not a valid database
tests\bugs\core_4964_test.py:116: AssertionError
Debug build of Firebird sends the real auth errors to client in addition to logging it into firebird.log. Because of this the test's output is not as expected. It is a false negative.