@Override
    public void deleteUser(String username) {
        String sql = "DELETE FROM users WHERE username=?";
        try {
            jt.update(sql, username);
        } catch (CannotGetJdbcConnectionException e) {
            LogUtil.FATAL_LOG.error("[db-error] " + e.toString(), e);
            throw e;
        }
    }
@Test
    void testDeleteUser() {
        externalUserPersistService.deleteUser("username");
        
        String sql = "DELETE FROM users WHERE username=?";
        Mockito.verify(jdbcTemplate).update(sql, "username");
    }