WireMock Pact

It will get the requests from WireMock and create Pact JSON files on the filesystem. The Pact JSON can be published to a Pactflow broker with curl, see example in this readme.

This repostory contains:

• wiremock-pact-lib - A library that can transform WireMock ServeEvent:s to Pact JSON.
• wiremock-pact-extension-junit5 - A WireMock extension, and JUnit 5 extension, that is intended to ease usage of the library.
• wiremock-pact-example-springboot-app - A SpringBoot application that shows how it can be used.

Use case

One simple use case to quickly show what this solves. It will take the requests, exactly as the system under test is performing them, and create the Pact JSON with that information. If you are already using WireMock in your integration tests, this tool should make it very easy to produce Pact JSON.

Usage - Junit 5

The extension is both a WireMock extension and a JUnit 5 extension. When using wiremock-spring-boot it can be configured like this in a base class of your tests:

import com.github.tomakehurst.wiremock.core.WireMockConfiguration;
import com.maciejwalkowiak.wiremock.spring.ConfigureWireMock;
import com.maciejwalkowiak.wiremock.spring.EnableWireMock;
import com.maciejwalkowiak.wiremock.spring.WireMockConfigurationCustomizer;
import org.junit.jupiter.api.extension.RegisterExtension;
import se.bjurr.wiremockpact.wiremockpactextensionjunit5.WireMockPactExtension;
import se.bjurr.wiremockpact.wiremockpactlib.api.WireMockPactConfig;

@EnableWireMock({
  @ConfigureWireMock(
      name = "wiremock-service-name",
      property = "wiremock.server.url",
      stubLocation = "wiremock",
      configurationCustomizers = {WireMockPactBaseTest.class})
})
public class WireMockPactBaseTest implements WireMockConfigurationCustomizer {
  @RegisterExtension
  static WireMockPactExtension WIREMOCK_PACT_EXTENSION =
      new WireMockPactExtension(
          WireMockPactConfig.builder() //
              .setConsumerDefaultValue("WireMockPactExample") //
              .setProviderDefaultValue("UnknownProvider") //
              .setPactJsonFolder("src/test/resources/pact-json"));

  @Override
  public void customize(
      final WireMockConfiguration configuration, final ConfigureWireMock options) {
    configuration.extensions(WIREMOCK_PACT_EXTENSION);
  }
}

Usage - Library

It can be used as a library.

public class ExampleTest {
  private static WireMockServer server;
  private static WireMockPactApi wireMockPactApi;

  @BeforeAll
  public static void beforeEach() throws IOException {
    server = new WireMockServer();
    server.start();

    stubFor(
        post(anyUrl())
            .willReturn(
                ok()
                .withHeader("content-type", "application/json")
                .withBody("""
                {"a":"b"}
                """))
            .withMetadata(
                new Metadata(
                    Map.of(
                        WireMockPactMetadata.METADATA_ATTR,
                        new WireMockPactMetadata()
                            .setProvider("some-specific-provider")))));

    wireMockPactApi =
        WireMockPactApi.create(
            new WireMockPactConfig()
                .setConsumerDefaultValue("my-service")
                .setProviderDefaultValue("unknown-service")
                .setPactJsonFolder("the/pact-json/folder"));
    wireMockPactApi.clearAllSaved();
  }

  @Test
  public void testInvoke() {
    // Do stuff that invokes WireMock...
  }

  @AfterAll
  public static void after() {
    for (final ServeEvent serveEvent : server.getAllServeEvents()) {
      wireMockPactApi.addServeEvent(serveEvent);
    }
    // Save pact-json to folder given in WireMockPactApi
    wireMockPactApi.saveAll();
    server.stop();
  }
}

Stateful Behaviour

WireMock has support for stateful behaviour. This is picked up by this tool and used to construct the provider states. You can also set the providerStates in the metadata of the mappings, see Mappings metadata.

Mappings metadata

This tool uses the metadata of WireMock mappings when generating Pact JSON.

You can adjust any mappings file like this to specify the provider:

{
  "id" : "d68fb4e2-48ed-40d2-bc73-0a18f54f3ece",
  "request" : {
    "urlPattern" : "/animals/1",
    "method" : "GET"
  },
  "response" : {
    "status" : 202
  },
  "uuid" : "d68fb4e2-48ed-40d2-bc73-0a18f54f3ece",
+  "metadata": {
+   "wireMockPactSettings": {
+     "provider":"some-other-system"
+   }
+  }
}

Or programmatically:

    stubFor(
        post(anyUrl())
            .withMetadata(
                new Metadata(
                    Map.of(
                        WireMockPactMetadata.METADATA_ATTR,
                        new WireMockPactMetadata()
                            .setProvider("some-specific-provider")))));

You can adjust any mappings file like this to specify the provider states:

{
  "id" : "d68fb4e2-48ed-40d2-bc73-0a18f54f3ece",
  "request" : {
    "urlPattern" : "/animals/1",
    "method" : "GET"
  },
  "response" : {
    "status" : 202
  },
  "uuid" : "d68fb4e2-48ed-40d2-bc73-0a18f54f3ece",
+  "metadata": {
+   "wireMockPactSettings": {
+     "providerStates": ["state1"]
+   }
+  }
}

Or programmatically:

    stubFor(
        post(anyUrl())
            .withMetadata(
                new Metadata(
                    Map.of(
                        WireMockPactMetadata.METADATA_ATTR,
                        new WireMockPactMetadata()
                            .setProviderStatesDefaultValue(Arrays.asList("state1"))))));

Publishing to Pact broker

Pact has a CLI tool that can be used for publishing the contracts. But it requires Ruby or Docker. If you don't have that, perhaps curl is an option. There is a shell script here that can also be used via NPM.

You may want to use something like git-changelog-command-line to get the next version.

There is a test-server at https://test.pactflow.io/ that can be accessed with user dXfltyFMgNOFZAxr8io9wJ37iUpY42M and password O5AIZWxelWbLvqMd8PkAVycBJh2Psyg1.

current_version=$(npx git-changelog-command-line \
  --patch-version-pattern "^fix.*" \
  --print-current-version)
git_hash=`git rev-parse --short HEAD`
participant_version_number="$current_version-$git_hash"

npx pactflow-publish-sh \
 --username=dXfltyFMgNOFZAxr8io9wJ37iUpY42M \
 --password=O5AIZWxelWbLvqMd8PkAVycBJh2Psyg1 \
 --pactflow-broker-url=https://test.pactflow.io/contracts/publish \
 --build-url=http://whatever/ \
 --pact-json-folder=wiremock-pact-example-springboot-app/src/test/resources/pact-json \
 --participant-version-number=$participant_version_number