Sping Boot 项目它使用SecurityContext。
它的大多数Rest控制器和服务都依赖于其登录用户的角色，用于验证目的。所以在测试过程中，我需要一个用户登录。
请告诉我单元测试代码的例子，为Spring Boot ，涉及登录用户的过程。

@RunWith(PowerMockRunner.class)
@PrepareForTest({SecurityContextHolder.class,AuthenticationManager.class,UserRepository.class,UserCreationRequestRepository.class,        PasswordEncoder.class,AuthorityRepository.class,CacheManager.class,POMasterCompanyRepository.class,BranchRepository.class})
public class BOAuthControllerTest {

@Autowired
private WebApplicationContext context;

@Mock
private AuthenticationManager authenticationManager;

@Mock
private UserRepository userRepository;
@Mock
private UserCreationRequestRepository userCreationRequestRepository;
@Mock
private PasswordEncoder passwordEncoder;
@Mock
private AuthorityRepository authorityRepository;
@Mock
private CacheManager cacheManager;
@Mock
private POMasterCompanyRepository poMasterCompanyRepository;
@Mock
private BranchRepository branchRepository;
private UserService userService;

private MockMvc mockMvc;

@Before
public void setup() {

    userService = new UserService(userRepository, passwordEncoder, authorityRepository, cacheManager, userCreationRequestRepository,
            poMasterCompanyRepository,branchRepository);

    UsernamePasswordAuthenticationToken authenticationToken =
            new UsernamePasswordAuthenticationToken("admin","admin");
    Authentication authentication = this.authenticationManager.authenticate(authenticationToken);
    SecurityContextHolder.getContext().setAuthentication(authentication);
    SecurityContext securityContext = new SecurityContextImpl();
    securityContext.setAuthentication(authentication);

            System.out.println(authenticationToken==null?"null":"not null");
    System.out.println(authenticationManager==null?"null":"not null");
    System.out.println(authentication==null?"null":"not null");
    System.out.println(SecurityContextHolder.getContext()==null?"null":"not null");
    System.out.println(SecurityContextHolder.getContext().getAuthentication()==null?"null":"not null");
    System.out.println(SecurityContextHolder.getContext().getAuthentication().getName());
    System.out.println(securityContext.getAuthentication().getName());

    PowerMockito.mockStatic(SecurityContextHolder.class);
    when(SecurityContextHolder.getContext()).thenReturn(securityContext);

    System.out.println(userService.getUserWithAuthorities().isPresent());
}

@Test
public void loginAvailableForAll() throws Exception {

    System.out.println(userService.getUserWithAuthorities().isPresent());

}

}