### Question:
UsersJdbcAuthzRepository extends AbstractJdbcRepository implements UsersAuthzRepository { @Override public List<Users> findUsersByUsername(String username) { String sql = " select u.* from users u where u.archived = 0 "; if (StringUtils.isNotEmpty(username)) { sql += " and u.username = ? order by u.id desc "; return this.jdbcTemplate.query(sql, usersRowMapper, username); } sql += " order by u.id desc "; return this.jdbcTemplate.query(sql, usersRowMapper); }  @Override List<Users> findUsersByUsername(String username); @Override List<Roles> findAvailableRolesList(); @Override Users findByUsername(String username); @Override int saveUsers(final Users users); @Override Roles findRolesByGuid(String guid); @Override void insertUserRoles(final int userId, final int rolesId); @Override List<Roles> findUsersRolesList(String usersGuid); @Override List<String> findPermissionsByRoles(String rolesGuid);  }### Answer:
@Test public void testFindUsersByUsername() throws Exception { List<Users> list = usersJdbcRepository.findUsersByUsername("user"); assertNotNull(list); assertTrue(list.isEmpty()); list = usersJdbcRepository.findUsersByUsername(""); assertNotNull(list); assertTrue(list.isEmpty()); list = usersJdbcRepository.findUsersByUsername(null); assertNotNull(list); assertTrue(list.isEmpty()); }