Spring MVC Rest Controller Tests

Using JsonPath in MockMVC Test

BeerController

@RequestMapping("/api/v1/beer")
@RestController
public class BeerController {

    private final BeerService beerService;

    @GetMapping(path = {"/{beerId}"},produces = { "application/json" })
    public ResponseEntity<BeerDto>  getBeerById(@PathVariable("beerId") UUID beerId){

        return new ResponseEntity<>(beerService.findBeerById(beerId), HttpStatus.OK);
    }
}

BeerControllerTest

import static org.hamcrest.core.Is.is;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.BDDMockito.given;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;

@ExtendWith(MockitoExtension.class)
class BeerControllerTest {

    @Mock
    BeerService beerService;

    @InjectMocks
    BeerController beerController;

    MockMvc mockMvc;

    BeerDto validBeer;

    @BeforeEach
    void setUp() {
        validBeer = BeerDto.builder().id(UUID.randomUUID())
                .version(1)
                .beerName("Beer1")
                .beerStyle(BeerStyleEnum.PALE_ALE)
                .price(new BigDecimal("12.99"))
                .quantityOnHand(4)
                .upc(123456789012L)
                .createdDate(OffsetDateTime.now())
                .lastModifiedDate(OffsetDateTime.now())
                .build();

        mockMvc = MockMvcBuilders.standaloneSetup(beerController).build();
    }

    @Test
    void testGetBeerById() throws Exception {
        given(beerService.findBeerById(any())).willReturn(validBeer);

        mockMvc.perform(get("/api/v1/beer/" + validBeer.getId()))
                .andExpect(status().isOk())
                .andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(jsonPath("$.id", is(validBeer.getId().toString())))
                .andExpect(jsonPath("$.beerName", is("Beer1")));

    }
}

Using JsonPath with List

BeerController

@RequestMapping("/api/v1/beer")
@RestController
public class BeerController {

    private static final Integer DEFAULT_PAGE_NUMBER = 0;
    private static final Integer DEFAULT_PAGE_SIZE = 25;

    private final BeerService beerService;

    public BeerController(BeerService beerService) {
        this.beerService = beerService;
    }

    @GetMapping(produces = { "application/json" })
    public ResponseEntity<BeerPagedList> listBeers(@RequestParam(value = "pageNumber", required = false) Integer pageNumber,
                                                   @RequestParam(value = "pageSize", required = false) Integer pageSize,
                                                   @RequestParam(value = "beerName", required = false) String beerName,
                                                   @RequestParam(value = "beerStyle", required = false) BeerStyleEnum beerStyle){

        if (pageNumber == null || pageNumber < 0){
            pageNumber = DEFAULT_PAGE_NUMBER;
        }

        if (pageSize == null || pageSize < 1) {
            pageSize = DEFAULT_PAGE_SIZE;
        }

        BeerPagedList beerList = beerService.listBeers(beerName, beerStyle, PageRequest.of(pageNumber, pageSize));

        return new ResponseEntity<>(beerList, HttpStatus.OK);
    }
}

BeerControllerTest

@ExtendWith(MockitoExtension.class)
class BeerControllerTest {

    @Mock
    BeerService beerService;

    @InjectMocks
    BeerController beerController;

    MockMvc mockMvc;

    BeerDto validBeer;

    @BeforeEach
    void setUp() {
        validBeer = BeerDto.builder().id(UUID.randomUUID())
                .version(1)
                .beerName("Beer1")
                .beerStyle(BeerStyleEnum.PALE_ALE)
                .price(new BigDecimal("12.99"))
                .quantityOnHand(4)
                .upc(123456789012L)
                .createdDate(OffsetDateTime.now())
                .lastModifiedDate(OffsetDateTime.now())
                .build();

        mockMvc = MockMvcBuilders.standaloneSetup(beerController).build();
    }

    @DisplayName("List Ops - ")
    @Nested
    public class TestListOperations {

        @Captor
        ArgumentCaptor<String> beerNameCaptor;

        @Captor
        ArgumentCaptor<BeerStyleEnum> beerStyleEnumCaptor;

        @Captor
        ArgumentCaptor<PageRequest> pageRequestCaptor;

        BeerPagedList beerPagedList;

        @BeforeEach
        void setUp() {
            List<BeerDto> beers = new ArrayList<>();
            beers.add(validBeer);
            beers.add(BeerDto.builder().id(UUID.randomUUID())
                    .version(1)
                    .beerName("Beer4")
                    .upc(123123123122L)
                    .beerStyle(BeerStyleEnum.PALE_ALE)
                    .price(new BigDecimal("12.99"))
                    .quantityOnHand(66)
                    .createdDate(OffsetDateTime.now())
                    .lastModifiedDate(OffsetDateTime.now())
                    .build());

            beerPagedList = new BeerPagedList(beers, PageRequest.of(1, 1), 2L);

            given(beerService.listBeers(beerNameCaptor.capture(), 
                    beerStyleEnumCaptor.capture(),
                    pageRequestCaptor.capture())).willReturn(beerPagedList);

            System.out.println(beerPagedList);
        }

        @DisplayName("Test list beers - no parameters")
        @Test
        void testListBeers() throws Exception {
            mockMvc.perform(get("/api/v1/beer")
                        .accept(MediaType.APPLICATION_JSON))
                    .andExpect(status().isOk())
                    .andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8))
                    .andExpect(jsonPath("$.content", hasSize(2)))
                    .andExpect(jsonPath("$.content[0].id", is(validBeer.getId().toString())));
        }
    }
}

Using Custom Message Converter with Spring MVC Test

BeerControllerTest

@ExtendWith(MockitoExtension.class)
class BeerControllerTest {

    @Mock
    BeerService beerService;

    @InjectMocks
    BeerController beerController;

    MockMvc mockMvc;

    BeerDto validBeer;

    @BeforeEach
    void setUp() {
        validBeer = BeerDto.builder().id(UUID.randomUUID())
                .version(1)
                .beerName("Beer1")
                .beerStyle(BeerStyleEnum.PALE_ALE)
                .price(new BigDecimal("12.99"))
                .quantityOnHand(4)
                .upc(123456789012L)
                .createdDate(OffsetDateTime.now())
                .lastModifiedDate(OffsetDateTime.now())
                .build();

        mockMvc = MockMvcBuilders.standaloneSetup(beerController)
                .setMessageConverters(jackson2HttpMessageConverter()) // Newly added
                .build();
    }

    @Test
    void testGetBeerById() throws Exception {
        DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssZ");

        given(beerService.findBeerById(any())).willReturn(validBeer);

       MvcResult result=  mockMvc.perform(get("/api/v1/beer/" + validBeer.getId()))
                .andExpect(status().isOk())
                .andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(jsonPath("$.id", is(validBeer.getId().toString())))
                .andExpect(jsonPath("$.beerName", is("Beer1")))
                .andExpect(jsonPath("$.createdDate",
                        is(dateTimeFormatter.format(validBeer.getCreatedDate()))))
               .andReturn();

        System.out.println(result.getResponse().getContentAsString());

    }

    @DisplayName("List Ops - ")
    @Nested
    public class TestListOperations {

        @Captor
        ArgumentCaptor<String> beerNameCaptor;

        @Captor
        ArgumentCaptor<BeerStyleEnum> beerStyleEnumCaptor;

        @Captor
        ArgumentCaptor<PageRequest> pageRequestCaptor;

        BeerPagedList beerPagedList;

        @BeforeEach
        void setUp() {
            List<BeerDto> beers = new ArrayList<>();
            beers.add(validBeer);
            beers.add(BeerDto.builder().id(UUID.randomUUID())
                    .version(1)
                    .beerName("Beer4")
                    .upc(123123123122L)
                    .beerStyle(BeerStyleEnum.PALE_ALE)
                    .price(new BigDecimal("12.99"))
                    .quantityOnHand(66)
                    .createdDate(OffsetDateTime.now())
                    .lastModifiedDate(OffsetDateTime.now())
                    .build());

            beerPagedList = new BeerPagedList(beers, PageRequest.of(1, 1), 2L);

            given(beerService.listBeers(beerNameCaptor.capture(), beerStyleEnumCaptor.capture(),
                    pageRequestCaptor.capture())).willReturn(beerPagedList);
        }

        @DisplayName("Test list beers - no parameters")
        @Test
        void testListBeers() throws Exception {
            mockMvc.perform(get("/api/v1/beer")
                        .accept(MediaType.APPLICATION_JSON))
                    .andExpect(status().isOk())
                    .andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8))
                    .andExpect(jsonPath("$.content", hasSize(2)))
                    .andExpect(jsonPath("$.content[0].id", is(validBeer.getId().toString())));
        }
    }

    // Coming up with a Customized implementation of the Jackson configuration
    public MappingJackson2HttpMessageConverter jackson2HttpMessageConverter(){
        ObjectMapper objectMapper = new ObjectMapper();

        // Customizing the objectMapper to properly parse timestamps
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        objectMapper.configure(SerializationFeature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS, true);
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);

        objectMapper.registerModule(new JavaTimeModule());
        return new MappingJackson2HttpMessageConverter(objectMapper);
    }
}

@WebMvc Test Slice

Using Curated Message Converter with Spring Boot

// Sets up the WebMvcTest Slice
@WebMvcTest(BeerController.class)
class BeerControllerTest {

    // Spring is going to inject it
    @MockBean
    BeerService beerService;

    @Autowired
    MockMvc mockMvc;

    BeerDto validBeer;

    @BeforeEach
    void setUp() {
        validBeer = BeerDto.builder().id(UUID.randomUUID())
                .version(1)
                .beerName("Beer1")
                .beerStyle(BeerStyleEnum.PALE_ALE)
                .price(new BigDecimal("12.99"))
                .quantityOnHand(4)
                .upc(123456789012L)
                .createdDate(OffsetDateTime.now())
                .lastModifiedDate(OffsetDateTime.now())
                .build();

        // Spring context will initialize the MockMvc
        // via auto-configuration of Spring Boot
    }

    @AfterEach
    void tearDown() {

        // beerService is a Spring component now,
        // Mockito knows it's a mock instance,
        // doesn't know to which context it is used
        reset(beerService);
    }

    @Test
    void testGetBeerById() throws Exception {
        DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ssZ");

        given(beerService.findBeerById(any())).willReturn(validBeer);

       MvcResult result=  mockMvc.perform(get("/api/v1/beer/" + validBeer.getId()))
                .andExpect(status().isOk())
                .andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8))
                .andExpect(jsonPath("$.id", is(validBeer.getId().toString())))
                .andExpect(jsonPath("$.beerName", is("Beer1")))
                .andExpect(jsonPath("$.createdDate",
                        is(dateTimeFormatter.format(validBeer.getCreatedDate()))))
               .andReturn();

        System.out.println(result.getResponse().getContentAsString());
    }

    @DisplayName("List Ops - ")
    @Nested
    public class TestListOperations {

        @Captor
        ArgumentCaptor<String> beerNameCaptor;

        @Captor
        ArgumentCaptor<BeerStyleEnum> beerStyleEnumCaptor;

        @Captor
        ArgumentCaptor<PageRequest> pageRequestCaptor;

        BeerPagedList beerPagedList;

        @BeforeEach
        void setUp() {
            List<BeerDto> beers = new ArrayList<>();
            beers.add(validBeer);
            beers.add(BeerDto.builder().id(UUID.randomUUID())
                    .version(1)
                    .beerName("Beer4")
                    .upc(123123123122L)
                    .beerStyle(BeerStyleEnum.PALE_ALE)
                    .price(new BigDecimal("12.99"))
                    .quantityOnHand(66)
                    .createdDate(OffsetDateTime.now())
                    .lastModifiedDate(OffsetDateTime.now())
                    .build());

            beerPagedList = new BeerPagedList(beers, PageRequest.of(1, 1), 2L);

            given(beerService.listBeers(beerNameCaptor.capture(), beerStyleEnumCaptor.capture(),
                    pageRequestCaptor.capture())).willReturn(beerPagedList);
        }

        @DisplayName("Test list beers - no parameters")
        @Test
        void testListBeers() throws Exception {
            mockMvc.perform(get("/api/v1/beer")
                        .accept(MediaType.APPLICATION_JSON))
                    .andExpect(status().isOk())
                    .andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8))
                    .andExpect(jsonPath("$.content", hasSize(2)))
                    .andExpect(jsonPath("$.content[0].id", is(validBeer.getId().toString())));
        }

        // Allowing Spring Boot to manage the Jackson configuration
    }
}

Using TestRestTemplate

BeerControllerIT

//Creating the web environment and the embedded server
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class BeerControllerIT {

    @Autowired
    private TestRestTemplate restTemplate;

    @Test
    void testListBeers() {
        BeerPagedList beerPagedList = restTemplate.getForObject("/api/v1/beer", BeerPagedList.class);

        assertThat(beerPagedList.getContent()).hasSize(3);
    }
}