Define a pact between service consumers and providers, enabling "consumer driven contract" testing.

1. Install pact mock service:

   1. Install Ruby and Ruby Gems

   2. Write a Gemfile:

      source 'https://rubygems.org'
      gem 'pact-mock_service', '~> 0.7.0'

   3. Run bundler to get the gems: gem install bundler && bundle install

2. Install composer: curl -sS https://getcomposer.org/installer | php

3. Install dependencies: php composer.phar install

4. Write a phpunit test similar to the following:

   public function testMyProvider() {
     $client = new ZooClient('https://localhost:1234');
     $alligatorProvider = Pact::mockService([
       'consumer' => 'Alligator Consumer',
       'provider' => 'Alligator Provider',
       'port' => 1234
     ]);
     $alligatorProvider
       ->given("an alligator with the name Mary exists")
       ->uponReceiving("a request for an alligator")
       ->withRequest("get", "/alligators/Mary", [
         "Accept" => "application/json"
       ])->willRespondWith(200, [
         "Content-Type" => "application/json"
       ], [
         "name" => "Mary"
       ]);
     $alligatorProvider->run(function() use ($client) {
       $alligator = $client->getAlligatorByName('Mary');
       $this->assertInstanceOf("Alligator", $alligator);
       $this->assertEquals("Mary", $alligator->getName());
     });
   }

5. Start the mock server: bundle exec pact-mock-service -p 1234 --pact-specification-version 2.0.0 -l log/pact.logs --pact-dir tmp/pacts

6. Run phpunit: ./vendor/bin/phpunit

7. Inspect the pact file in tmp/pacts