### Question:
TppDataUploaderController implements TppDataUploaderRestApi { @Override public ResponseEntity<Map<String, String>> uploadTransactions(MultipartFile file) { log.info("uploading transactions"); Map<String, String> response = transactionService.uploadUserTransaction(file); log.info("upload response contains {} errors", response.size()); return ResponseEntity.ok(response); }  @Override ResponseEntity<String> uploadData(MultipartFile file); @Override ResponseEntity<Resource> generateData(boolean generatePayments, String currency); @Override ResponseEntity<String> generateIban(String tppId); @Override ResponseEntity<Map<String, String>> uploadTransactions(MultipartFile file); @Override ResponseEntity<Resource> downloadTransactionTemplate();  }### Answer:
@Test void uploadTransactions() throws IOException { when(transactionService.uploadUserTransaction(any())).thenReturn(Collections.EMPTY_MAP); ResponseEntity<Map<String, String>> response = uploaderController.uploadTransactions(resolveMultipartFile("transactions_template.csv")); assertTrue(response.getStatusCode().is2xxSuccessful()); assertTrue(Objects.requireNonNull(response.getBody()).isEmpty()); assertEquals(response.getBody(), new HashMap<String, String>()); }