Contract Test using PACT

ApiContractTest.java

import au.com.dius.pact.consumer.dsl.PactDslWithProvider;
import au.com.dius.pact.consumer.junit5.PactConsumerTestExt;
import au.com.dius.pact.consumer.junit5.PactTestFor;
import au.com.dius.pact.core.model.RequestResponsePact;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;

import java.util.HashMap;
import java.util.Map;

@ExtendWith(PactConsumerTestExt.class)
public class ApiContractTest {

    @PactTestFor(providerName = "ProviderService", hostInterface = "localhost", port = "8080")
    public class PactConsumerTest {

        @Pact(consumer = "ConsumerService")
        public RequestResponsePact createPact(PactDslWithProvider builder) {
            Map<String, String> headers = new HashMap<>();
            headers.put("Content-Type", "application/json");

            return builder
                    .given("Test State")
                    .uponReceiving("A request to /api/data")
                    .path("/api/data")
                    .method("GET")
                    .willRespondWith()
                    .status(200)
                    .headers(headers)
                    .body("{\"name\":\"test\",\"status\":\"success\"}")
                    .toPact();
        }

        @Test
        @PactTestFor(pactMethod = "createPact")
        void testConsumerService() {
            // Here you would use an HTTP client to make the request to the provider API
            // and verify the response matches the expected results defined in the pact
        }
    }
}

GenericApiContractTest.java

import au.com.dius.pact.consumer.dsl.PactDslWithProvider;
import au.com.dius.pact.consumer.junit5.PactConsumerTestExt;
import au.com.dius.pact.consumer.junit5.PactTestFor;
import au.com.dius.pact.core.model.RequestResponsePact;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;

import java.util.HashMap;
import java.util.Map;

@ExtendWith(PactConsumerTestExt.class)
public class GenericApiContractTest {

    // Utility class for creating PACT contracts
    static class PactContractGenerator {
        static RequestResponsePact createContract(String providerName, String interactionDescription,
                                                  String requestPath, String requestMethod,
                                                  int expectedStatus, String responseBody) {
            Map<String, String> headers = new HashMap<>();
            headers.put("Content-Type", "application/json");

            return PactDslWithProvider
                    .consumer("ConsumerService")
                    .given("Test State")
                    .uponReceiving(interactionDescription)
                    .path(requestPath)
                    .method(requestMethod)
                    .willRespondWith()
                    .status(expectedStatus)
                    .headers(headers)
                    .body(responseBody)
                    .toPact();
        }
    }

    @PactTestFor(providerName = "ProviderService", hostInterface = "localhost", port = "8080")
    public class PactConsumerTest {

        @Pact(consumer = "ConsumerService")
        public RequestResponsePact createPact() {
            // Example usage of the utility class
            return PactContractGenerator.createContract("ProviderService",
                    "A request to /api/data", "/api/data", "GET",
                    200, "{\"name\":\"test\",\"status\":\"success\"}");
        }

        @Test
        @PactTestFor(pactMethod = "createPact")
        void testConsumerService() {
            // Implement your HTTP request and response verification here
        }
    }
}

import au.com.dius.pact.provider.junit5.PactVerificationContext;
import au.com.dius.pact.provider.junit5.PactVerificationInvocationContextProvider;
import au.com.dius.pact.provider.junit5.PactVerifyProvider;
import org.junit.jupiter.api.TestTemplate;
import org.junit.jupiter.api.extension.ExtendWith;

@ExtendWith(PactVerificationInvocationContextProvider.class)
public class UserProviderTest {

    @TestTemplate
    @ExtendWith(PactVerificationInvocationContextProvider.class)
    void pactVerificationTestTemplate(PactVerificationContext context) {
        context.verifyInteraction();
    }

    @PactVerifyProvider("A request for user")
    public String verifyGetUser() {
        return "{\"id\": 1, \"name\": \"John Doe\"}";
    }
}