First time writing tests (Service Layer)

Question

Service class:

package personal.progresscompaninon.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.stereotype.Service;
import personal.progresscompaninon.dto.PasswordChangeDto;
import personal.progresscompaninon.exception.*;
import personal.progresscompaninon.model.Role;
import personal.progresscompaninon.model.User;
import personal.progresscompaninon.repository.RoleRepository;
import personal.progresscompaninon.repository.UserRepository;
import javax.validation.Valid;
import java.util.ArrayList;
import java.util.Collection;
@Service
public class UserService implements UserDetailsService {
 @Autowired
 private final UserRepository userRepository;
 @Autowired
 private RoleRepository roleRepository;
 BCryptPasswordEncoder bCryptPasswordEncoder;
 public UserService(UserRepository userRepository, RoleRepository roleRepository) {
 this.userRepository = userRepository;
 this.roleRepository = roleRepository;
 bCryptPasswordEncoder = new BCryptPasswordEncoder();
 }
public void addUser(@Valid User user) {
 if (findByEmail(user.getEmail()) != null) {
 throw new UserAlreadyRegisteredException("User already registered");
 }
 user.getRoles().add(roleRepository.findByRole("ROLE_USER"));
 user.setPassword(bCryptPasswordEncoder.encode(user.getPassword()));
 userRepository.save(user);
 }
 public void changePassword(@Valid PasswordChangeDto passwords) {
 User user = getLoggedInUser();
 if (bCryptPasswordEncoder.matches(passwords.getOldPassword(), user.getPassword())) {
 if (passwordValidator(passwords.getNewPassword())) {
 userRepository.changePassword(bCryptPasswordEncoder.encode(passwords.getNewPassword()), user.getEmail());
 System.out.println(user.getPassword());
 }
 } else {
 throw new WrongPasswordException("Old password didn't match");
 }
 }
 public User findByEmail(String email) {
 return userRepository.findByEmail(email);
 }
 public boolean passwordValidator(String password) {
 return password.length() > 8;
 }
 public User getLoggedInUser() {
 return userRepository.findByEmail(SecurityContextHolder.getContext().getAuthentication().getName());
 }
 public User getUser(long id) {
 return userRepository.findById(id).get();
 }
 public void deleteUser(long id) {
 userRepository.deleteById(id);
 }
@Override
 public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
 User user = userRepository.findByEmail(username);
 if (user == null) {
 throw new UsernameNotFoundException("User not found in the database");
 }
 Collection<SimpleGrantedAuthority> authorities = new ArrayList<>();
 for (Role role : user.getRoles()) {
 authorities.add(new SimpleGrantedAuthority(role.getName()));
 }
 return new org.springframework.security.core.userdetails.User(user.getEmail(), user.getPassword(), authorities);
 }

Tests:

@ExtendWith(MockitoExtension.class)
@ExtendWith(SpringExtension.class)
class UserServiceTest {
 @Mock
 private UserRepository userRepositoryMock;
 @Mock
 private RoleRepository roleRepositoryMock;
 private UserService userService;
 @BeforeEach
 public void setup() {
 userService = new UserService(userRepositoryMock, roleRepositoryMock);
 }
 @Test
 void shouldAddUser() {
 String role = "ROLE_USER";
 User user = new User(0L, "test", "test", "[email protected]", "yesyesyes", new ArrayList<>(), null);
 Mockito.when(roleRepositoryMock.findByRole(role)).thenReturn(new Role(1L, role, null));
 userService.addUser(user);
 Mockito.verify(roleRepositoryMock).findByRole(role);
 Mockito.verify(userRepositoryMock).save(user);
 }
 @Test
 void shouldThrowAlreadyRegisteredException() {
 UserService userService = new UserService(userRepositoryMock, roleRepositoryMock);
 String email = "[email protected]";
 User user = new User(0L, "test", "test", email, "yesyesyes", new ArrayList<>(), null);
 Mockito.when(userRepositoryMock.findByEmail(email)).thenReturn(user);
 Exception exception = assertThrows(UserAlreadyRegisteredException.class, () -> userService.addUser(user));
 Assert.assertEquals("User already registered", exception.getMessage());
 }
 @Test
 void invalidPasswordTest() {
 UserService userService = new UserService(null, null);
 String password = "qwert";
 assertFalse(userService.passwordValidator(password));
 }
}

Been learning Spring boot recently and wrote a simple CRUD api, I have never done any kind of testing before and this is my first attempt writing tests for service layer

• Toby Speight: Could you please edit so that the title describes the purpose of the code under test? We really need to understand the motivational context to give good reviews - knowing that these are your first tests doesn't help with that. Thanks!
• TorbenPutkonen: You're starting to learn unit testing? Well, I wish I had seen this before I started doing unit tests... youtube.com/watch?v=EZ05e7EMOLM
• BCdotWEB: The current question title, which states your concerns about the code, applies to too many questions on this site to be useful. The site standard is for the title to simply state the task accomplished by the code. Please see How do I ask a good question?.

Answer 1

The test looks good. except that you do not have to initialize the UserService again inside the Test like below, since @BeforeEach is being called every time before each test

 @Test
 void shouldThrowAlreadyRegisteredException() {
UserService userService = new UserService(userRepositoryMock, roleRepositoryMock);
}