java - 忽略 Mockito 中测试方法内部的无效方法

Question

在 Account 类中，我有一个方法 public Account reserveA() 我想测试，在 reserveA 中称为方法 public Bank DAO.createB( )。有没有办法在测试方法中调用 reserveA() 但忽略调用 DAO.createB()？这些方法都无效。我试过:

doNothing().when(Account).reserveA(param1, param2);

但这不是正确的方法。

Answer 1

doNothing() 只为 void 方法保留。如果您的方法返回了一些东西，那么您也需要这样做(或抛出异常)。根据您的 Account.reserveString() 的复杂性，如果在其他地方使用结果，您可能需要模拟的不仅仅是这个方法调用。

尝试在非 void 方法上使用 doNothing() 会导致错误:

org.mockito.exceptions.base.MockitoException: 
Only void methods can doNothing()!
Example of correct use of doNothing():
    doNothing().
    doThrow(new RuntimeException())
    .when(mock).someVoidMethod();
Above means:
someVoidMethod() does nothing the 1st time but throws an exception the 2nd time is called

考虑这样的类:

@Component
public class BankDao {
    public BankDao() {}

    public void createVoid() {
        System.out.println("sth - 1");
    }

    public String createString(){
        return "sth - 2";
    }
}

@Service
public class Account {
    @Autowired
    private final BankDao DAO;

    public Account(BankDao dao) {
        this.DAO = dao;
    }
    public void reserveVoid() {
        System.out.println("before");
        DAO.createVoid();
        System.out.println("after");
    }
    public void reserveString() {
        System.out.println(DAO.createString());
    }
}

为其创建测试类:

@RunWith(MockitoJUnitRunner.class)
public class AccountTest {
    @Mock
    private BankDao bankDao;

    @InjectMocks
    private Account account;

    @Test
    public void reserveVoid_mockBankDaoAndDontUseRealMethod() {
        doNothing().when(bankDao).createVoid();
        account.reserveVoid();
    }

    @Test
    public void reserveString_mockBankDaoAndDontUseRealMethod() {
        when(bankDao.createString()).thenReturn("nothing");
        account.reserveString();
    }
}

运行这样的测试会产生:

nothing
before
after

如果将@Mock 更改为@Spy 并删除带有doNothing() 和when() 的行，那么您将调用原始方法。结果将是:

sth - 2
before
sth - 1
after