Spring Rest Template is not returning the data

Question

I am trying to write an integration test for my spring application, I have an api which insert some default data, I run call this api after my test gets initialized

@PostConstruct
public void inti() {
    ResponseEntity<String> response = restTemplate.getForEntity("/api/default", String.class);
    assertEquals("Default values are not inserted successfully", "lala", response.getBody());
}

This passed and I can see in the database default values.

In my test I try to fetch some data but the returned data is 0 although I tested the api manually and its working

@Test
public void shouldReturnDeliveryNotes() {
    ResponseEntity<PagedResources<DeliveryNote>> allDeliveryNotes = restTemplate.exchange("/api/deliverynotes/all?start=0&length=1000",HttpMethod.GET,null,  new ParameterizedTypeReference<PagedResources<DeliveryNote>>() {});
    assertNotEquals("Should have default delivery notes", 0, allDeliveryNotes.getBody().getContent().size());   
}

I put some log in the api to see the returned data size and I see the returned data when the test is run is correct which means my test is hitting the right api and the api fetch the data.

@GetMapping("/all")
public ResponseEntity<Page<DeliveryNoteDTO>> getAllDeliveryNote(@RequestParam(value = "start", required = false) int start, @RequestParam(value ="length", required = false) int length) {
    Pageable pageable = new OffsetBasedPageRequest(start, (length ==0? Integer.MAX_VALUE: length));
    List<DeliveryNote> page = this.deliveryNoteService.getAllDeliverNotes();
    List<DeliveryNoteDTO> dtoList =page.stream().map(post -> convertToDto(post)).collect(Collectors.toList());
    Page<DeliveryNoteDTO> pageDto = new PageImpl<>(dtoList, pageable, dtoList.size());
    System.out.println("size = "+pageDto.getNumberOfElements());
    return new ResponseEntity<Page<DeliveryNoteDTO>>(pageDto,HttpStatus.OK);
}

Any help is appreciated

Answer 1

The problem is I am returning Page while in my restTemplate I am expecting PagedResources, it would make sense to just return page but I need a concrete class , I would use PageImpl but the problem is that PageImple does not have a default constructor which RestTemplate use to map the response, so What I did I created a new class and extended the PageImpl just as mentioned in the accepted answer of this question

Spring RestTemplate with paginated API