I am trying to test CompletableFuture.supplyAsync function with mockito but the test is not completing probably because the completable future is not returning. I am not sure what I am missing in the code. Can anyone please help.
I have written the code as follows. So there are UserService class which returns User, UserEntityService class which returns users entities and a validation class to check if the entities belongs to the user or not.
I want to test if the passed entities belongs to user or not.
class UserService {
CompletableFuture<User> getUser(String userName) {
log.info("Fetching User with username {}", userName);
return CompletableFuture.supplyAsync(
() -> getUserByPortalUserName(userName));
}
}
class UserEntityService {
CompletableFuture<List<UserEntity>> getUserEntities(Long userId) {
log.info("Retrieving all entities for user id {}", userId);
return CompletableFuture.supplyAsync(
() -> getAllByUserId(userId));
}
}
class UserValidationService {
public boolean validateUserCounterparty(UserRequest request)
throws ExecutionException, InterruptedException {
CompletableFuture<Boolean> result = userService.getUser(request.getUserName())
.thenCompose(user -> userEntityService.getUserEntities(user.getUserId()))
.thenCompose(userEntities -> validate(userEntities, request.getUserEntities()));
Boolean validationStatus = result.get();
if (!validationStatus) {
log.error("Validation failed for user name {}", request.getUserName());
}
return validationStatus;
}
}
And the test case is written as
@ExtendWith(MockitoExtension.class)
class UserValidationServiceTest {
@Mock
UserService userService;
@Mock
UserEntityService userEntityService;
@InjectMocks
UserValidationService userValidationService;
@Before
public void init() {
MockitoAnnotations.openMocks(this);
}
@Test
public void validateUser() throws ExecutionException, InterruptedException {
CompletableFuture<User> userFuture = new CompletableFuture<>();
CompletableFuture<List<UserEntity>> userEntityFuture = new CompletableFuture<>();
Mockito.doReturn(userFuture).when(userService).getUser(anyString());
Mockito.doReturn(userEntityFuture).when(userEntityService).getUserEntities(anyLong());
UserRequest request = UserRequest.builder()
.userName("admin")
.userEntities(List.of("US", "ASIA", "EUROPE")).build();
boolean result = validationService.validateUserCounterparty(request);
assertTrue(result);
}
}
On executing this test, it goes into infinite loop and never stops. I guess its because the completable future is not returning but I dont have enough knowledge on how to prevent it.
What modification should I do to prevent it?
CodePudding user response:
In your test method you're creating CompletableFuture
instances using new
. JavaDoc states:
public CompletableFuture()
Creates a new incomplete CompletableFuture.
So the objects you're creating are never completing, that's why the test is running infinitely. It's not actually a loop, but waiting on a blocking operation to be finished, which never happens.
What you need to do is define a CompletableFuture
that completes - immediately or after some time. The simplest way of doing that is by using the static completedFuture() method:
CompletableFuture<User> userFuture =
CompletableFuture.completedFuture(new User());
CompletableFuture<List<UserEntity>> userEntityFuture =
CompletableFuture.completedFuture(List.of(new UserEntity()));
Thanks to that given objects are returned and the code can be executed fully. You can test errors in a similar way by using the failedFuture() method.
I've created a GitHub repo with a minimal reproducible example - the test presented there passes.