I am new in unit testing and use JUnit in my Java (Spring Boot) app. I sometimes need to test update methods, but when I search on the web, there is not a proper example or suggestion. So, could you please clarify me how to test the following update method? I think this may require a different approach than testing void. I also thought that while testing first mocking the record and then update its field and then update. Finally retrieve the record again and compare the updated properties. But I think there may be more proper approach than this inexperienced one.
public PriceDTO update(UUID priceUuid, PriceRequest request) {
Price price = priceRepository
.findByUuid(priceUuid)
.orElseThrow(() -> new EntityNotFoundException(PRICE));
mapRequestToEntity(request, price);
Price updated = priceRepository.saveAndFlush(price);
return new PriceDTO(updated);
}
private void mapRequestToEntity(PriceRequest request, Price entity) {
entity.setPriceAmount(request.getPriceAmount());
// set other props
}
You need to mock the behavior of the class object priceRepository.
So you will have to write something like below to begin :
// priceRepository should be mocked in the test class
Mockito.when(priceRepository.findByUuid(any(UUID.class))).thenReturn(new Price());
You would need to do something along the following lines:
public class ServiceTest {
@Mock
private PriceRepository priceRepository;
(...)
@Test
public void shouldUpdatePrice() throws Exception {
// Arrange
UUID priceUuid = // build the Price UUID
PriceRequest priceUpdateRequest = // build the Price update request
Price originalPrice = // build the original Price
doReturn(originalPrice).when(this.priceRepository).findByUuid(isA(UUID.class));
doAnswer(AdditionalAnswers.returnsFirstArg()).when(this.priceRepository).saveAndFlush(isA(Price.class));
// Act
PriceDTO updatedPrice = this.service.update(priceUuid, priceUpdateRequest);
// Assert
// here you need to assert that updatedPrice is as you expect according to originalPrice and priceUpdateRequest
}
}
So if your only intention is to verify if you called save, then something like this is probably what you are looking for:
@ExtendWith(MockitoExtension.class)
public class ServiceTest {
@Mock
private PriceRepository priceRepository;
@InjectMocks
private Service service;
@Test
public void update() throws Exception {
// Given
Price price = new Price();
price.setUid(UUID.randomUUID());
price.setPriceAmount(100);
when(priceRepository.findByUid(price.getUid()))
.thenReturn(price);
ArgumentCaptor<Price> priceArgument =
ArgumentCaptor.forClass(Price.class);
when(incidentRepository.saveAndFlush(priceArgument.capture()))
.thenAnswer(iom -> iom.getArgument(0));
// When
PriceRequest priceRequest = new PriceRequest();
priceRequest.setPriceAmount(123);
PriceDTO updatedPrice = this.service.update(price.getUid(), priceUpdateRequest);
// Then
assertThat(priceArgument.getValue().getPriceAmount())
.isEqualTo(123);
}
}