Encoding problem in Spring Boot MockMvc tests

I'm implementing integration tests for my Spring Boot application using MockMvc. The problem is that I need to use russian characters in my request/response bodies and they keep changing to unreadable symbols

Here's my config:

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, classes = InfoApplicationConfig.class)
@TestPropertySource(properties = {"spring.config.location=classpath:application-it.yml"})
@AutoConfigureMockMvc
@DirtiesContext(classMode = DirtiesContext.ClassMode.AFTER_EACH_TEST_METHOD)
public class TerminalControllerIT {

    @Autowired
    MockMvc mockMvc;

    @LocalServerPort
    private int port;

    private String baseUrl = "http://localhost";

    private final String validTerminalId = "eee00000-0000-0000-0000-000000000000";

    private final String invalidTerminalId = "abc00000-0000-0000-0000-000000123456";

    private NewTerminalDto testSubject;

    @Autowired
    private static ObjectMapper objectMapper;

    @Autowired
    private TerminalRepository terminalRepository;

    @BeforeEach
    public void setUp() {
        testSubject = NewTerminalDto.builder().country("Россия").region("Москва").city("Москва")
                .street("Ленина").buildingNumber("12A")
                .roomNumber("101").terminalCoordinate("55.7558,37.6176")
                .postCode("123456").terminalNumber("123")
                .isClosed(false).cashDepositWithdrawal(false).moneyTransfer(true).payment(true).nfc(true)
                .banknotesPerPack(100)
                .biometrics(false).encashmentService(true).cashDeposit(true)
                .openingTime("08:00")
                .closingTime("18:00")
                .build();
        baseUrl = baseUrl.concat(":" + port).concat("/api/v1/info-service/terminals");
    }

Test 1:

@Test
    @DisplayName("Should return terminal by id")
    void getTerminalInfoByIdPositiveTest() throws Exception {
        MvcResult result = mockMvc.perform(get(baseUrl + "/" + validTerminalId)
                        .characterEncoding("UTF-8")
                        .contentType(MediaType.APPLICATION_JSON))
                .andExpect(status().isOk())
                .andReturn();

        String jsonResponse = result.getResponse().getContentAsString();
        TerminalGetResponse actualResponse = objectMapper.readValue(jsonResponse, TerminalGetResponse.class);

        assertNotNull(actualResponse);
        assertNotNull(actualResponse.getTerminalNumber());
        assertNotNull(actualResponse.getRegion());
        assertEquals("ТРМ-001", actualResponse.getTerminalNumber());
        assertEquals("Москва", actualResponse.getRegion());
    }

Response:

Expected :ТРМ-001
Actual   :ТРÐ-001

Test 2:

 @Test
    @DisplayName("Adding branch")
    void addBranch() throws Exception {
        BranchPayload body = BranchStubs.createBranchPayload(0);

        mockMvc.perform(post(baseUrl)
                        .content(objectMapper.writeValueAsBytes(body))
                        .contentType(MediaType.APPLICATION_JSON_VALUE)
                        .characterEncoding("UTF-8"))
                .andExpect(status().isOk());

        BankBranchesModel bankBranchesModel = BankBranchesModel.builder().branchNumber(body.getBranchNumber()).build();

        assertNotNull(bankBranchesRepository.findOne(Example.of(bankBranchesModel)).orElse(null));
    }

Result:

MockHttpServletRequest:
      HTTP Method = POST
      Request URI = /api/v1/info-service/branches
       Parameters = {}
          Headers = [Content-Type:"application/json;charset=UTF-8", Content-Length:"907"]
             Body = {"branchNumber":"8500","country":"??????","region":"?????????? ???????","city":"????????","street":"???????????","buildingNumber":"5","postCode":"117997","branchCoordinate":"55.696225, 37.544539","ramp":true,"phoneNumber":"74955555550","isClosed":false,"openingTime":"00:00","closingTime":"23:55","dayOfWeek":["???????????","???????","?????","???????","???????"],"currencyExchange":true,"foreignCurrency":true,"moneyTransfer":true,"cashWithdrawal":true,"payment":true,"replenishCard":true,"replenishAccount":true,"hasDeposit":true,"hasCredit":true,"consultation":true,"insurance":true,"bik":"044525220","kpp":"773643002","inn":"7707083890","paymentAccount":"40702810562000000000","correspondentAccount":"30101810400000000225","bankNameFull":"?? «FinTech Bank»","okpo":"09610477","ogrn":"1027700057410","swift":"LIBBRUMM007"}
    Session Attrs = {}

...

MockHttpServletResponse:
           Status = 400
    Error message = null
          Headers = [Content-Type:"application/json"]
     Content type = application/json
             Body = {"bankNameFull":"must match \"^(?!\\s*$)[0-9A-Za-z?-??-? !\"#$%&'()*+,\\-./:;<=>?@\\[\\\\\\]^_{|}~]{1,30}$\""}
    Forwarded URL = null
   Redirected URL = null
          Cookies = []

Tried to set encoding in test class properties / for objectMapper / for mockMvc - none of that worked for me Also tried doing it in my migration files which actually doesn;t make sense because characters in request are already messed up

Upd Forgot to mention that the app works just fine when testing with Swagger or Postman

After trying every possible solution I stumbled upon russian forums where my problem was discussed consistently. So, changing Windows default locale to UTF-8 worked for me in the end Here's a short guide: https://exploratory.io/note/exploratory/Enabling-UTF-8-on-Windows-hYc3yWL0