Test Result showing null while performing jUnit5 Test - spring-boot

Question

I am writing a jUnit5 test to test my getUserByEmail(String email) using Mockito and when running the test, it is failing.
#SpringBootTest
#ExtendWith(MockitoExtension.class)
class UserServiceTest {
#MockBean
private UsersRepository userRepository;
#Autowired
private UserService userService;
#Test
void check_email_existInDB_thenReturn_True() {
// given - precondition or setup
UserDetails userdetails2 = new UserDetails(101L, "Anthony Ji", "anthony#gmail.com", "password2");
userRepository.save(userdetails2);
// when - action or behaviour that we are going test
when(userRepository.save(userdetails2)).thenReturn(userdetails2);
// then - verify the result or output using assert statements
assertEquals(userdetails2.getEmail(), userService.getUserByEmail("anthony#gmail.com"));
//assertTrue(userService.getUserByEmail(userdetails2.getEmail()));
}
}
This is my interface with extending of JPARepository
public interface UsersRepository extends JpaRepository<UserDetails, Long>{
}
This is my service level class
#Service
public interface UserService {
public Optional<UserDetails> getUserByEmail(String email);
public UserDetails saveUserDetails(UserDetails userDetails);
}
And this is the serviceImpl Class..
#Service
public class UserServiceImpl implements UserService{
#Autowired
private UsersRepository userRepository;
#Override
public Optional<UserDetails> getUserByEmail(String email) {
List<UserDetails> allUsers = this.userRepository.findAll();
Optional<UserDetails> userInfo = allUsers.stream().filter(user -> user.getEmail().equalsIgnoreCase(email)).findAny();
return userInfo;
}
#Override
public UserDetails saveUserDetails(UserDetails userDetails) {
UserDetails savedUserDetails = this.userRepository.save(userDetails);
return savedUserDetails;
}
}
and finally, this is my controller class while using jersey framework.
#Path(value = "/user")
public class RegistrationResources {
private static Logger logger = LoggerFactory.getLogger(RegistrationResources.class);
#Autowired
private UserService userService;
#POST
#Path("/registration")
#Produces(MediaType.APPLICATION_JSON)
#Consumes(MediaType.APPLICATION_JSON)
public Response registerUser(UserDetails userDetails, #Context UriInfo uriInfo) {
logger.info("Inside the registration resource and registering the user");
boolean isEmailExists = isEmailExists(userDetails.getEmail());
if(isEmailExists) {
logger.info("Email Already Registered");
return Response.status(404).entity("Email Address already registered").build();
}
else {
this.userService.saveUserDetails(userDetails);
logger.info("User successfully registered");
return Response.status(200).entity("User successfully registered").build();
}
}
public boolean isEmailExists(String email) {
UserDetails userByEmail = this.userService.getUserByEmail(email).orElse(null);
if(userByEmail == null) {
return false;
}
return true;
}
I tried as above explained in the code.