### Question:
CheckUtils { public static boolean checkUserName(String userName) { return regexChecks(userName, Constants.REGEX_USER_NAME); } private  CheckUtils(); static boolean checkUserName(String userName); static boolean checkEmail(String email); static Map<String, Object> checkDesc(String desc); static boolean checkOtherParams(String otherParams); static boolean checkPassword(String password); static boolean checkPhone(String phone); static boolean checkTaskNodeParameters(String parameter, String taskType); static boolean checkUserParams(String userName, String password, String email, String phone);  }### Answer:
@Test public void testCheckUserName() { assertTrue(CheckUtils.checkUserName("test01")); assertFalse(CheckUtils.checkUserName(null)); assertFalse(CheckUtils.checkUserName("test01@abc")); }