@SpringBootTest(
    webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT,
    classes = BackendApplication.class)
@TestExecutionListeners({
    DependencyInjectionTestExecutionListener.class,
    DirtiesContextTestExecutionListener.class,
    WithSecurityContextTestExecutionListener.class})
public class OfferControllerTest extends AbstractTestNGSpringContextTests
{
    private MockMvc mockMvc;

    @Autowired
    private WebApplicationContext context;

    @Mock
    private UserRepository гserRepository;

    @BeforeClass
    public void setUp()
    {
        mockMvc = MockMvcBuilders.webAppContextSetup(context).apply(springSecurity())
            .build();
    }

    @Test
    public void setOffers() throws Exception
    {
        ObjectMapper objectMapper = new ObjectMapper();
        OfferDTO offerDTO = new OfferDTO().setDescription("description");

        Account account = new Account();
        account.setK(new K());
        User user = new User();
        user.setAccount(account);

        when(userRepository.findByEmailEquals(any())).thenReturn(Optional.of(user));

        mockMvc.perform(post("/offers")
            .accept(MediaType.APPLICATION_JSON)
            .contentType(MediaType.APPLICATION_JSON)
            .content(objectMapper.writeValueAsString(ImmutableList.of(offerDTO))))
            .andExpect(status().isOk());
    }
}

        K ref = userRepository.findByEmailEquals(user.getUsername()).get().getAccount().getK();