Add mock client factory for test purpose.

ClientFactory/MockFactory.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Http\HttplugBundle\ClientFactory;
+
+use Http\Mock\Client;
+
+/**
+ * @author Gary PEGEOT <garypegeot@gmail.com>
+ */
+class MockFactory implements ClientFactory
+{
+    /**
+     * @var Client
+     */
+    private $client;
+
+    /**
+     * @param Client $client
+     */
+    public function setClient(Client $client)
+    {
+        $this->client = $client;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function createClient(array $config = [])
+    {
+        if (!class_exists(Client::class)) {
+            throw new \LogicException('To use the mock adapter you need to install the "php-http/mock-client" package.');
+        }
+
+        if (!$this->client) {
+            $this->client = new Client();
+        }
+
+        return $this->client;
+    }
+}

DependencyInjection/HttplugExtension.php

@@ -12,6 +12,7 @@
 use Http\Message\Authentication\BasicAuth;
 use Http\Message\Authentication\Bearer;
 use Http\Message\Authentication\Wsse;
+use Http\Mock\Client as MockClient;
 use Psr\Http\Message\UriInterface;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\ChildDefinition;
@@ -40,6 +41,9 @@ public function load(array $configs, ContainerBuilder $container)
 
         $loader->load('services.xml');
         $loader->load('plugins.xml');
+        if (\class_exists(MockClient::class)) {
+            $loader->load('mock-client.xml');
+        }
 
         // Register default services
         foreach ($config['classes'] as $service => $class) {

Resources/config/mock-client.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<container xmlns="http://symfony.com/schema/dic/services"
+           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+           xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
+
+    <services>
+        <service id="httplug.client.mock" class="Http\Mock\Client" public="true" />
+        <service id="httplug.factory.mock" class="Http\HttplugBundle\ClientFactory\MockFactory" public="false">
+            <call method="setClient">
+                <argument type="service" id="httplug.client.mock" />
+            </call>
+        </service>
+    </services>
+</container>

Tests/Unit/ClientFactory/MockFactoryTest.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ * This file is part of the HttplugBundle package.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Http\HttplugBundle\Tests\Unit\ClientFactory;
+
+use Http\HttplugBundle\ClientFactory\MockFactory;
+use Http\Mock\Client;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @author Gary PEGEOT <garypegeot@gmail.com>
+ */
+class MockFactoryTest extends TestCase
+{
+    public function testCreateClient()
+    {
+        $factory = new MockFactory();
+        $client = $factory->createClient();
+
+        $this->assertInstanceOf(Client::class, $client);
+
+        $client = new Client();
+
+        $factory->setClient($client);
+
+        $this->assertEquals($client, $factory->createClient());
+    }
+}

Tests/Unit/DependencyInjection/HttplugExtensionTest.php

@@ -134,6 +134,7 @@ public function testClientPlugins()
             $this->assertContainerBuilderHasService($id);
         }
         $this->assertContainerBuilderHasServiceDefinitionWithArgument('httplug.client.acme', 1, $pluginReferences);
+        $this->assertContainerBuilderHasService('httplug.client.mock');
     }
 
     /**

composer.json

@@ -60,6 +60,9 @@
     "conflict": {
         "php-http/guzzle6-adapter": "<1.1"
     },
+    "suggest": {
+        "php-http/mock-client": "Add this to your require-dev section to mock HTTP responses easily"
+    },
     "autoload": {
         "psr-4": {
             "Http\\HttplugBundle\\": ""