测试接口还是类？

Question

我对java很陌生，我对用JUnit和Mockito测试代码感到困惑。

我在github上创建了一个项目，任务是为AccountService编写Junit测试，这是一个接口。我不知道的是我要测试什么？接口还是实现接口的类？

这是AccountService

public interface AccountService {
    public Operation deposit(String accountNumber, int amount);
    public Operation withdraw(String accountNumber, int amount);
    public OperationsDto history(String accountNumber);
}

下面是AccountService实现

@Service
public class AccountServiceImpl implements  AccountService {

    @Autowired
    private AccountRepository accountRepository;
    @Autowired
    private OperationRepository operationRepository;

    @Autowired
    OperationConverter operationConverter;


    public Operation deposit(String accountNumber, int amount) {
        checkAmount (amount);

        AccountEntity account = getAccount (accountNumber);

        int balance =  account.getBalance();
        balance = balance + amount;

        OperationEntity operation = new OperationEntity();
        operation.setAccount(accountNumber);
        operation.setAmount(amount);
        operation.setType(OperationType.DEPOSIT.toString());
        operation.setDate(DateUtil.getCurrentDate());
        operation.setBalance(balance);

        operationRepository.save(operation);

        //update account balance
        account.setBalance(balance);
        accountRepository.save(account);

        return  operationConverter.convert(operation);
    }

    public Operation withdraw(String accountNumber, int amount) {
        checkAmount (amount);

        AccountEntity account = getAccount (accountNumber);

        int balance = account.getBalance();
        balance = balance - amount;
        if(balance < 0){
            throw new OperationException(Constants.ERROR_INVALID_OPERATION);
        }

        OperationEntity operation = new OperationEntity();
        operation.setBalance(balance);
        operation.setAccount(accountNumber);
        operation.setAmount(amount);
        operation.setType(OperationType.WITHDRAW.toString());
        operation.setDate(DateUtil.getCurrentDate());

        operationRepository.save(operation);

        //update account balance
        account.setBalance(balance);
        accountRepository.save(account);

        return  operationConverter.convert(operation);
    }

    public OperationsDto history(String accountNumber) {
        List<OperationEntity>  operations = 
        operationRepository.findByAccount(accountNumber);
        return operationConverter.convertList(operations);
    }

    private AccountEntity getAccount(String accountNumber){

        AccountEntity account = 
        accountRepository.findByNumber(accountNumber);

        if(account == null) {
            throw new AccountException(Constants.ERROR_INVALID_ACCOUNT);
        }

        return account;
    }

    private void checkAmount (int amount) {
        if(amount < 0){
            throw new OperationException(Constants.ERROR_INVALID_OPERATION);
        }
    }
}

Answer 1

您应该测试实现，因此，类。

接口应该只用于注射。因此，看看您已经发布的代码，您应该在一个AccountServiceImpl类(或类似的类)中测试这个类。

在这个单元测试中，您应该模拟AccountRepository、OperationRepository和OperationConverter。在测试单元中，您应该只测试对测试感兴趣的类，而不是它的依赖项。因此，您可以使用@Autowired注入接口。通过这种方式，您可以使用模拟框架来模拟您的类依赖关系，隔离您需要测试的单元。

看看您发布的类:您正在使用注释注入三个bean。我很确定这些类型都是接口。部署应用程序时，Spring将负责在启动容器(或正确运行Spring )之后注入实际实现。当您运行这个类时，您希望隔离它。测试应该尽可能是原子化的。使用Mockito和正确的JUnit运行程序，您将为注入的bean提供一个假实现。使用Mockito，您可以知道这个假实现应该如何响应某个请求。因此，您可以使用AccountServiceImpl的实现，模拟它的所有依赖项，而不是只测试该类中包含的逻辑。您不测试接口，因为接口只代表调用服务的契约，而不是它的实现。

@RunWith(MockitoJUnitRunner.class)
public class AccountServiceTest {

@Mock
private AccountRepository accountRepository;

@Mock
private OperationRepository operationRepository;

@Mock
OperationConverter operationConverter;

@InjectMocks
private AccountServiceImpl accountService;

@Before
public void setUp() {
    /* here goes before-class init logic */
}

@Test
public void testMethod1() {
    /* here you test a method*/
}

@Test
public void testMethod2() {
    /* here you test another method*/
}
}

这就是测试类应该显示的方式。