GraphQL

Since GraphQL is essentially HTTP you can write a contract for it by creating a standard HTTP contract with an additional metadata entry with key verifier and a mapping tool=graphql.

Groovy

import org.springframework.cloud.contract.spec.Contract

Contract.make {

	request {
		method(POST())
		url("/graphql")
		headers {
			contentType("application/json")
		}
		body('''
{
	"query":"query queryName($personName: String!) {\\n  personToCheck(name: $personName) {\\n    name\\n    age\\n  }\\n}\\n\\n\\n\\n",
	"variables":{"personName":"Old Enough"},
	"operationName":"queryName"
}
''')
	}

	response {
		status(200)
		headers {
			contentType("application/json")
		}
		body('''\
{
  "data": {
    "personToCheck": {
      "name": "Old Enough",
      "age": "40"
    }
  }
}
''')
	}
	metadata(verifier: [
	        tool: "graphql"
	])
}

YAML

---
request:
  method: "POST"
  url: "/graphql"
  headers:
    Content-Type: "application/json"
  body:
    query: "query queryName($personName: String!) { personToCheck(name: $personName)
      {         name    age  } }"
    variables:
      personName: "Old Enough"
    operationName: "queryName"
  matchers:
    headers:
      - key: "Content-Type"
        regex: "application/json.*"
        regexType: "as_string"
response:
  status: 200
  headers:
    Content-Type: "application/json"
  body:
    data:
      personToCheck:
        name: "Old Enough"
        age: "40"
  matchers:
    headers:
      - key: "Content-Type"
        regex: "application/json.*"
        regexType: "as_string"
name: "shouldRetrieveOldEnoughPerson"
metadata:
  verifier:
    tool: "graphql"

Adding the metadata section will change the way the default, WireMock stub is built. It will now use the Spring Cloud Contract request matcher, so that e.g. the query part of the GraphQL request gets compared against the real request by ignoring whitespaces.

Producer Side Setup

On the producer side your configuration can look as follows.

Maven

<plugin>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-contract-maven-plugin</artifactId>
    <version>${spring-cloud-contract.version}</version>
    <extensions>true</extensions>
    <configuration>
        <testMode>EXPLICIT</testMode>
        <baseClassForTests>com.example.BaseClass</baseClassForTests>
    </configuration>
</plugin>

Gradle

contracts {
	testMode = "EXPLICIT"
	baseClassForTests = "com.example.BaseClass"
}

The base class would set up the application running on a random port.

Base Class

@SpringBootTest(classes = ProducerApplication.class,
		properties = "graphql.servlet.websocket.enabled=false",
		webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public abstract class BaseClass {

	@LocalServerPort int port;

	@BeforeEach
	public void setup() {
		RestAssured.baseURI = "http://localhost:" + port;
	}
}

Consumer Side Setup

Example of a consumer side test of the GraphQL API.

Consumer Side Test

@SpringBootTest(webEnvironment = WebEnvironment.NONE)
public class BeerControllerGraphQLTest {

	@RegisterExtension
	static StubRunnerExtension rule = new StubRunnerExtension()
			.downloadStub("com.example","beer-api-producer-graphql")
			.stubsMode(StubRunnerProperties.StubsMode.LOCAL);

	private static final String REQUEST_BODY = "{\n"
			+ "\"query\":\"query queryName($personName: String!) {\\n  personToCheck(name: $personName) {\\n    name\\n    age\\n  }\\n}\","
			+ "\"variables\":{\"personName\":\"Old Enough\"},\n"
			+ "\"operationName\":\"queryName\"\n"
			+ "}";

	@Test
	public void should_send_a_graphql_request() {
		ResponseEntity<String> responseEntity = new RestTemplate()
				.exchange(RequestEntity
						.post(URI.create("http://localhost:" + rule.findStubUrl("beer-api-producer-graphql").getPort() + "/graphql"))
						.contentType(MediaType.APPLICATION_JSON)
						.body(REQUEST_BODY), String.class);

		BDDAssertions.then(responseEntity.getStatusCodeValue()).isEqualTo(200);

	}
}