How can I get dynamic response when using Spring Cloud Contract?

Question

org.springframework.cloud.contract.spec.Contract.make {
    request { 
        method 'GET' 
        url '/weather' 
    }
    response {
        status 200
        body([
               "weather": value(regex("(SUNNY|WINDY|CLOUDY|RAINY)"))
        ])
}

I know Groovy DSL is able to generate a random value, Like the code above. But the Groovy DSL just generate a static stub, and it will always return the same response as I requested.

How can I get a random weather without re-generate the stubs in this case?

Answer 1

You can't, that's because WireMock stub needs a concrete value on the response side. The only thing you could do is to reference the request from the response and then the request can have random input. In general, your tests shouldn't depend on random response.

Answer 2

I know is an old question but I found a workaround solution to achieve that using dynamic values from the given request, you can set a custom headers using $regex then use as output response.

Groovy

request {
    method 'GET'
    url """/v1/persons/${anyUuid()}"""
    headers {
        contentType('application/json')
        header 'Authorization' : 'Mocked Return Data'
        header 'nameMocked' : $(regex('[a-zA-Z0-9]{5, 30}'))
        header 'dateMocked' : $(regex('(0[1-9]|[12][0-9]|3[01])/(0[1-9]|1[012])/([0-9]{4})'))
        header 'typeMocked' : $(regex('CONSUMER|COMMERCIAL'))
    }
}
response {
    status 200
    body(
        """
        {
          "name": "${fromRequest().header('nameMocked')}",
          "date": "${fromRequest().header('dateMocked')}",
          "type": "${fromRequest().header('typeMocked')}",
        }
        """
    )
    headers {
        contentType('application/json')
    }
}

BaseClass

class PersonDto {
    private UUID id;
    private String name;
    private LocalDate date;
    private PersonType type;
}   


@Slf4j
@RunWith(SpringRunner.class)
@ContextConfiguration(classes = JacksonAutoConfiguration.class)
public abstract class BaseTest {
    @Autowired
    private ObjectMapper objectMapper;

    @Before
    public void setup() throws Exception {
        YourController yourController = spy(new YourController());
        //normal business mocks
        doAnswer((Answer<ResponseEntity>) invocation -> {
            HttpServletRequest currentRequest = getCurrentRequest();
            Map<String, String> map = Collections.list(currentRequest.getHeaderNames()).stream()
                .filter(n -> n.endsWith("Mocked"))
                .collect(Collectors.toMap(k -> k.replaceFirst("Mocked", ""), currentRequest::getHeader));
            return ResponseEntity.ok(objectMapper.convertValue(map, PersonDto.class)); //Convert map to dto
        }).when(YourController).getPerson(matches("([a-f0-9]{8}(-[a-f0-9]{4}){4}[a-f0-9]{8})"), eq("Mocked Return Data")); //This should match your request

        RestAssuredMockMvc.standaloneSetup(yourController);
    }

    private HttpServletRequest getCurrentRequest() {
        RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
        Assert.state(requestAttributes != null, "Could not find current request via RequestContextHolder");
        Assert.isInstanceOf(ServletRequestAttributes.class, requestAttributes);
        HttpServletRequest servletRequest = ((ServletRequestAttributes) requestAttributes).getRequest();
        Assert.state(servletRequest != null, "Could not find current HttpServletRequest");
        return servletRequest;
    }

}

Consumer example

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.DEFINED_PORT)
@AutoConfigureStubRunner(workOffline = true, ids = "groupId:artifactId:+:stubs:8083")
@DirtiesContext
public class ConsumerContractAT {

    @Test
    public void callApiGetShouldReturnDynamicMockedData() {
        Response response = RestAssured.given()
            .header(HttpHeaders.AUTHORIZATION, "Mocked Return Data")
            .header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
            .header("nameMocked", "Test")
            .header("typeMocked", "CONSUMER")
            .header("dobMocked", DateTimeFormatter.ofPattern("dd/MM/yyyy").format(LocalDate.of(2019, 10, 10)))
            .when()
            .get("/v1/persons/{tokeId}", UUID.randomUUID())
            .then()
            .statusCode(200)
            .extract().response();

        assertThat(response.jsonPath().getString("typeMocked")).isEqualTo("CONSUMER");
        assertThat(response.jsonPath().getString("name")).isEqualTo("Test");
        assertThat(response.jsonPath().getString("dob")).isEqualTo("10/10/2019");

        response = RestAssured.given()
            .header(HttpHeaders.AUTHORIZATION, "Mocked Return Data")
            .header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
            .header("nameMocked", "Test 2")
            .header("typeMocked", "COMMERCIAL")
            .header("dobMocked", DateTimeFormatter.ofPattern("dd/MM/yyyy").format(LocalDate.now()))
            .when()
            .get("/v1/persons/{tokeId}", UUID.randomUUID())
            .then()
            .statusCode(200)
            .extract().response();

        assertThat(response.jsonPath().getString("typeMocked")).isEqualTo("COMMERCIAL");
        assertThat(response.jsonPath().getString("name")).isEqualTo("Test 2");
        assertThat(response.jsonPath().getString("dob")).isEqualTo(DateTimeFormatter.ofPattern("dd/MM/yyyy").format(LocalDate.now()));
    }
}