Junit , Mockito Integration with Vertx - vert.x

Question

I am new vertx wanted to know which is the best junit framework and references that we should went through.
I tried using couple of things with mockito but services are not getting injected.
Please help in this.
UPDATE:
My TestClass looks something like this
public class GroupModeTest {
private static final Logger logger = LoggerFactory.getLogger(GroupMode.class);
public static GroupModeService service;
public static GroupModeDao dao;
private GroupMode groupMode;
private static GroupModeDao daoMock;
#BeforeAll
static void setup() {
logger.info("Starting Unit Tests for GroupMode");
daoMock = mock(GroupModeDao.class);
dao = new GroupModeDao();
service = new GroupModeService(daoMock);
}
#BeforeEach
void init() {
logger.info("Mocking new GroupMode Entity");
this.groupMode = new GroupMode();
}
#Test
public void testFakeWithMockito() throws IOException {
IGroupModeDao iGroupModeDao = mock(IGroupModeDao.class);
GroupMode groupMode = new GroupMode();
groupMode.setId(1L);
groupMode.setModeType("unique");
groupMode.setCreatedBy(1);
groupMode.setCreatedOn(LocalDateTime.now());
groupMode.setUpdatedBy(1);
groupMode.setUpdatedOn(LocalDateTime.now());
Single<Long> expected=Single.just(1L);
when(iGroupModeDao.create(groupMode)).thenReturn(expected);
GroupModeService groupModeService = new GroupModeService(iGroupModeDao);
Single<Long> actual= groupModeService.rxCreate("unique",1);
assertEquals(expected, actual);
}
}