Java怎样单测void类型的方法？-CFANZ编程社区

Java的Sevice层会有很多void类型的方法，比如save*、update*，这类方法只是做一些更新，不会有返回值，其单测不能根据方法的返回值来编写，只能采用特殊方法；

本方法环境：Mockito、testng

被测试的方法：

想要被测试的VOID方法

Java

@Override public void updateRuleName(Long ruleId, String newRuleName, Long ucId) { Assert.notNull(ruleId, "规则ID不能为Null"); Assert.notNull(newRuleName, "规则名称不能为Null"); Assert.notNull(ucId, "操作人的UCID不能为Null"); String cleanNewRuleName = StringUtils.trim(newRuleName); if (StringUtils.isBlank(cleanNewRuleName)) { throw new IllegalArgumentException("新的规则名称不能为空"); } // 查询规则对象 Rule rule = queryRuleById(ruleId); if (null == rule) { throw new IllegalDataException("没有查到该规则"); } rule.setRuleId(ruleId); rule.setRuleName(cleanNewRuleName); rule.setUpdateUcid(ucId); rule.setUpdateTime(new Date()); ruleDao.updateSelective(rule); }

CREATE TABLE `tcc` (
  `idx` INT(11),
  `typeid` INT(11),
  `value1` INT(11),
  `value2` INT(11),
   UNIQUE KEY(idx, typeid)
) ENGINE = INNODB DEFAULT CHARSET =utf8;
 
-- 第一条SQL的执行，会新增一条数据，本SQL多次执行，效果相同，因为后续的操作，变成了UPDATE
INSERT INTO tcc (idx, typeid, value1)
VALUES (1,2,3) ON DUPLICATE KEY UPDATE value1 =3;
 
-- 第二条SQL直接进行UPDATE，把新列的值update进去
INSERT INTO tcc (idx, typeid, value2)
VALUES (1,2,4) ON DUPLICATE KEY UPDATE value2 =4;

测试的方法：

void返回的方法测试

Java

@Test public void testUpdateRuleName() { Long ruleId = 1L; String newRuleName = "newRuleName"; Long ucId = 123L; List<Rule> rules = new ArrayList<Rule>(); Rule rule = new Rule(); rule.setRuleStatus((byte) DBValueSetting.RULE_STATUS_TAKE_EFFECT); rules.add(rule); // 查询规则对象 Map<String, Object> params = new HashMap<String, Object>(); params.put("ruleId", ruleId); Mockito.when(ruleDao.queryRulesByCondition(params)).thenReturn(rules); Mockito.doAnswer(new Answer<Object>() { public Object answer(InvocationOnMock invocation) { // 断点2：这里随后执行 Rule rule = (Rule) invocation.getArguments()[0]; Assert.assertTrue(rule.getRuleName().equals("newRuleName")); return null; } }).when(ruleDao).updateSelective(Mockito.any(Rule.class)); // 断点1：先执行到这里 ruleService.updateRuleName(ruleId, newRuleName, ucId); }

@Test
     public void testUpdateRuleName ( ) {
         Long ruleId = 1L ;
         String newRuleName = "newRuleName" ;
         Long ucId = 123L ;
        
         List <Rule> rules = new ArrayList <Rule> ( ) ;
         Rule rule = new Rule ( ) ;
         rule . setRuleStatus ( ( byte ) DBValueSetting . RULE_STATUS_TAKE_EFFECT ) ;
         rules . add ( rule ) ;
        
         // 查询规则对象
         Map < String , Object > params = new HashMap < String , Object > ( ) ;
         params . put ( "ruleId" , ruleId ) ;
         Mockito . when ( ruleDao . queryRulesByCondition ( params ) ) . thenReturn ( rules ) ;
        
         Mockito . doAnswer ( new Answer <Object> ( ) {
             public Object answer ( InvocationOnMock invocation ) {
                 // 断点2：这里随后执行
                 Rule rule = ( Rule ) invocation . getArguments ( ) [ 0 ] ;
                 Assert . assertTrue ( rule . getRuleName ( ) . equals ( "newRuleName" ) ) ;
                 return null ;
             }
         } ) . when ( ruleDao ) . updateSelective ( Mockito . any ( Rule . class ) ) ;
        
         // 断点1：先执行到这里
         ruleService . updateRuleName ( ruleId , newRuleName , ucId ) ;
     }

如注释所示，如果加了两个断点的话，执行的过程中，会先执行最后的调用行，端点1执行的过程中，会执行到端点2的stub，这时候在断点2可以获取到方法执行的入参，对入参进行Assert校验，即可实现目的；

new Anwer是个接口，其中只有一个方法，用于设置方法调用的代理执行入口

doAnswer的实现

Java

public interface Answer<T> { /** * @param invocation the invocation on the mock. * * @return the value to be returned * * @throws Throwable the throwable to be thrown */ T answer(InvocationOnMock invocation) throws Throwable; }

public interface Answer <T> {
     /**
     * @param invocation the invocation on the mock.
     *
     * @return the value to be returned
     *
     * @throws Throwable the throwable to be thrown
     */
     T answer ( InvocationOnMock invocation ) throws Throwable ;
}
————————————————

当代码执行到“ruleDao.updateSelective(rule);”的时候，会触发针对mock对象调用的拦截器，在拦截器中，会创建一个动态代理，动态代理的invocation就是new Answer中覆盖的方法；

使用拦截、代理两种方法，实现了对mock对象方法的入参、出参的设定和获取，使用这种方式，就可以校验VOID方法内部的执行类调用的情况；