1public class UserServiceTest {
 2
 3    @Mocked
 4    private UserDao userDao;
 5
 6    @Test
 7    public void couldCallUserDaoToAddUser() {
 8        new Expectations(){{
 9           userDao.findById(123);
10           result = "Yanbin";
11        }};
12
13        UserService userService = new UserService(userDao);
14        String user = userService.findBy(123);
15
16        assertThat(user).isEqualTo("Yanbin");  //这里断言成功也就证明了 userDao.findById(123) 方法被调用，参数必须是 123
17    }
18}

 1public class UserService {
 2    private ExternalApi external = ExternalApi.default();
 3    private UserDao userDao;
 4
 5    public UserService(UserDao userDao) {
 6        this.userDao = userDao;
 7    }
 8
 9    public User findUserById(int id) {
10        return userDao.findById(external.convertId(id));
11    }
12}

 1public class Handler implements RequestHandler<SNSEvent, String> {
 2
 3    private int threadPoolSize = getThreadPoolSizeFromEnv();
 4    private ExecutorService threadPool = Executors.newFixedThreadPool(threadPoolSize);
 5
 6    @Override
 7    public String handleRequest(SNSEvent snsEvent, Context context) {
 8        int configuredThreadPoolSize = getThreadPoolSizeFromEnv();
 9        if(configuredThreadPoolSize != threadPoolSize) {
10        threadPoolSize = configuredThreadPoolSize;
11        threadPool = Executors.newFixedThreadPool(threadPoolSize);
12    }
13
14    return "Hello Lambda";
15    }
16
17    private int getThreadPoolSizeFromEnv() {
18        return Integer.parseInt(System.getenv().getOrDefault("threadpool_size", "50"));
19    }
20}