Refactored the configuration of sessions

The configuration now makes sessions a first-class citizen instead of
being centered around drivers. This allows defining several session based
on the same driver type.
Instead of allowing other extensions to register their own sessions to add
new drivers, they can now register a DriverFactory in the MinkExtension
during the extension initialization to make a new driver type available.

behat.yml.dist

@@ -6,4 +6,6 @@ default:
   extensions:
     Behat\MinkExtension\Extension:
       base_url: http://en.wikipedia.org/
+      sessions:
+        default:
           goutte: ~

doc/index.rst

@@ -60,6 +60,8 @@ The easiest way to keep your suite updated is to use `Composer <http://getcompos
           extensions:
             Behat\MinkExtension\Extension:
               base_url:  'http://example.com'
+              sessions:
+                default:
                   goutte: ~
 
 Usage
@@ -161,21 +163,57 @@ Configuration
 MinkExtension comes with flexible configuration system, that gives you
 ability to configure Mink inside Behat to fulfil all your needs.
 
-Drivers
-~~~~~~~
+Sessions
+--------
 
-First of all, there's drivers enabling configuration. MinkExtension comes
-with support for 6 drivers out of the box:
-
-* ``GoutteDriver`` - default headless driver. It is used by default, which means
-  that if you didn't changed ``default_session`` (another parameter) - you should
-  always enable it.  In order to enable it, modify your ``behat.yml`` profile:
+You can register as many Mink session as you want. For each session, you
+will need to choose the driver you want to use.
 
     .. code-block:: yaml
 
         default:
             extensions:
                 Behat\MinkExtension\Extension:
+                    sessions:
+                        first_session:
+                            selenium2: ~
+                        second_session:
+                            goutte: ~
+                        third_session:
+                            selenium2: ~
+
+MinkExtension will set the default Mink session for each scenario based on
+the configuration settings ``default_session`` and ``javascript_session``
+and on scenario tags:
+
+* A scenario tagged with ``@mink:foo`` will use ``foo`` as default session;
+* A scenario tagged with ``@javascript`` will use the javascript session as default session;
+* Other scenarios will use the default session.
+
+If it is not configured explicitly, the javascript session is set to the first
+session using a javascript driver in the order of the configuration (it would
+be ``first_session`` in the example above as ``selenium2`` supports Javascript).
+If it is not configured explicitly, the default session is set to the first
+session using a non-javascript driver if any, or to the first javascript session
+otherwise (it would be ``second_session`` above as ``goutte`` does not support
+javascript).
+
+Drivers
+~~~~~~~
+
+First of all, there's drivers enabling configuration. MinkExtension comes
+with support for 6 drivers out of the box:
+
+* ``GoutteDriver`` - headless driver without JavaScript support. In order to use
+  it, modify your ``behat.yml`` profile:
+
+    .. code-block:: yaml
+
+        default:
+            extensions:
+                Behat\MinkExtension\Extension:
+                    sessions:
+                        my_session:
                             goutte: ~
 
 .. Tips : HTTPS and self-signed certificate
@@ -188,41 +226,38 @@ the following parameters to avoid the validation error triggered by Guzzle :
     default:
       extensions:
         Behat\MinkExtension\Extension:
+          sessions:
+            my_session:
               goutte:
                 guzzle_parameters:
                   ssl.certificate_authority: false
 
-* ``Selenium2Driver`` - default javascript driver. It is used by default for
-  ``@javascript`` tagged scenarios, which means that if you didn't changed
-  ``javascript_session`` (another parameter) - you should always enable it (only
-  if you use ``@javascript`` scenarios, of course).  In order to enable it,
-  modify your ``behat.yml`` profile:
+* ``Selenium2Driver`` - javascript driver. In order to use it, modify your
+  ``behat.yml`` profile:
 
     .. code-block:: yaml
 
         default:
             extensions:
                 Behat\MinkExtension\Extension:
+                    sessions:
+                        my_session:
                             selenium2: ~
 
 * ``SaucelabsDriver`` - special flavor of the Selenium2Driver configured to use the
-  selenium2 hosted installation of saucelabs.com. You could use it by setting it in
-  ``javascript_session`` to ``saucelabs`` and by marking scenarios as ``@javascript``
-  or simply by marking scenarios with ``mink:saucelabs`` (no need to switch
-  ``javascript_session`` in this case). In order to enable it, modify your ``behat.yml``
-  profile:
+  selenium2 hosted installation of saucelabs.com. In order to use it, modify your
+  ``behat.yml`` profile:
 
     .. code-block:: yaml
 
         default:
             extensions:
                 Behat\MinkExtension\Extension:
+                    sessions:
+                        my_session:
                             saucelabs: ~
 
-* ``SeleniumDriver`` - another javascript driver. You could use it by setting it
-  in ``javascript_session`` to ``selenium`` and by marking scenarios as ``@javascript``
-  or simply by marking scenarios with ``mink:selenium`` (no need to switch
-  ``javascript_session`` in this case). In order to enable it, modify your ``behat.yml``
+* ``SeleniumDriver`` - javascript driver. In order to use it, modify your ``behat.yml``
   profile:
 
     .. code-block:: yaml
@@ -230,12 +265,11 @@ the following parameters to avoid the validation error triggered by Guzzle :
         default:
             extensions:
                 Behat\MinkExtension\Extension:
+                    sessions:
+                        my_session:
                             selenium: ~
 
-* ``SahiDriver`` - another javascript driver. You could use it by setting it
-  in ``javascript_session`` to ``sahi`` and by marking scenarios as ``@javascript``
-  or simply by marking scenarios with ``mink:sahi`` (no need to switch
-  ``javascript_session`` in this case). In order to enable it, modify your ``behat.yml``
+* ``SahiDriver`` - javascript driver. In order to use it, modify your ``behat.yml``
   profile:
 
     .. code-block:: yaml
@@ -243,19 +277,20 @@ the following parameters to avoid the validation error triggered by Guzzle :
         default:
             extensions:
                 Behat\MinkExtension\Extension:
+                    sessions:
+                        my_session:
                             sahi: ~
 
-* ``ZombieDriver`` - zombie.js javascript headless driver. You could use it by setting it
-  in ``javascript_session`` to ``zombie`` and by marking scenarios as ``@javascript``
-  or simply by marking scenarios with ``mink:zombie`` (no need to switch
-  ``javascript_session`` in this case). In order to enable it, modify your ``behat.yml``
-  profile:
+* ``ZombieDriver`` - zombie.js javascript headless driver. In order to use it, modify
+  your ``behat.yml`` profile:
 
     .. code-block:: yaml
 
         default:
             extensions:
                 Behat\MinkExtension\Extension:
+                    sessions:
+                        default:
                             zombie: ~
 
 .. note::
@@ -300,9 +335,9 @@ There's other useful parameters, that you can use to configure your suite:
 * ``browser_name`` - meta-option, that defines which browser to use for Sahi,
   Selenium and Selenium2 drivers.
 * ``default_session`` - defines default session (driver) to be used for all
-  untagged scenarios. Could be any enabled driver name. Defaults to ``goutte``
+  untagged scenarios. Could be any enabled session name.
 * ``javascript_session`` - defines javascript session (driver) (the one, which
-  will be used for ``@javascript`` tagged scenarios). Could be any enabled driver
-  name. Defaults to ``selenium2``
+  will be used for ``@javascript`` tagged scenarios). Could be any enabled session
+  name.
 * ``mink_loader`` - path to a file loaded to make Mink available (useful when
   using the PHAR archive for Mink, useless when using Composer)

spec/Behat/MinkExtension/Listener/SessionsListenerSpec.php

@@ -6,13 +6,14 @@ use Behat\Behat\Tester\Event\ScenarioTested;
 use Behat\Gherkin\Node\FeatureNode;
 use Behat\Gherkin\Node\ScenarioNode;
 use Behat\Mink\Mink;
+use Behat\Testwork\ServiceContainer\Exception\ProcessingException;
 use PhpSpec\ObjectBehavior;
 
 class SessionsListenerSpec extends ObjectBehavior
 {
     function let(Mink $mink, ScenarioTested $event, FeatureNode $feature, ScenarioNode $scenario)
     {
-        $this->beConstructedWith($mink, array('default_session' => 'goutte', 'javascript_session' => 'selenium2'));
+        $this->beConstructedWith($mink, 'goutte', 'selenium2');
 
         $event->getFeature()->willReturn($feature);
         $event->getScenario()->willReturn($scenario);
@@ -54,6 +55,15 @@ class SessionsListenerSpec extends ObjectBehavior
         $this->prepareDefaultMinkSession($event);
     }
 
+    function it_fails_when_the_javascript_session_is_used_but_not_defined($event, $mink, $feature)
+    {
+        $this->beConstructedWith($mink, 'goutte', null);
+        $feature->getTags()->willReturn(array('javascript'));
+
+        $this->shouldThrow(new ProcessingException('The @javascript tag cannot be used without enabling a javascript session'))
+            ->duringPrepareDefaultMinkSession($event);
+    }
+
     function it_switches_to_a_named_session($event, $mink, $scenario)
     {
         $scenario->getTags()->willReturn(array('mink:test'));

spec/Behat/MinkExtension/ServiceContainer/Driver/GoutteFactorySpec.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace spec\Behat\MinkExtension\ServiceContainer\Driver;
+
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+
+class GoutteFactorySpec extends ObjectBehavior
+{
+    function it_is_a_driver_factory()
+    {
+        $this->shouldHaveType('Behat\MinkExtension\ServiceContainer\Driver\DriverFactory');
+    }
+
+    function it_is_named_goutte()
+    {
+        $this->getDriverName()->shouldReturn('goutte');
+    }
+
+    function it_does_not_support_javascript()
+    {
+        $this->supportsJavascript()->shouldBe(false);
+    }
+}

spec/Behat/MinkExtension/ServiceContainer/Driver/SahiFactorySpec.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace spec\Behat\MinkExtension\ServiceContainer\Driver;
+
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+
+class SahiFactorySpec extends ObjectBehavior
+{
+    function it_is_a_driver_factory()
+    {
+        $this->shouldHaveType('Behat\MinkExtension\ServiceContainer\Driver\DriverFactory');
+    }
+
+    function it_is_named_sahi()
+    {
+        $this->getDriverName()->shouldReturn('sahi');
+    }
+
+    function it_supports_javascript()
+    {
+        $this->supportsJavascript()->shouldBe(true);
+    }
+}

spec/Behat/MinkExtension/ServiceContainer/Driver/SaucelabsFactorySpec.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace spec\Behat\MinkExtension\ServiceContainer\Driver;
+
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+
+class SaucelabsFactorySpec extends ObjectBehavior
+{
+    function it_is_a_driver_factory()
+    {
+        $this->shouldHaveType('Behat\MinkExtension\ServiceContainer\Driver\DriverFactory');
+    }
+
+    function it_is_named_saucelabs()
+    {
+        $this->getDriverName()->shouldReturn('saucelabs');
+    }
+
+    function it_supports_javascript()
+    {
+        $this->supportsJavascript()->shouldBe(true);
+    }
+}

spec/Behat/MinkExtension/ServiceContainer/Driver/Selenium2FactorySpec.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace spec\Behat\MinkExtension\ServiceContainer\Driver;
+
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+
+class Selenium2FactorySpec extends ObjectBehavior
+{
+    function it_is_a_driver_factory()
+    {
+        $this->shouldHaveType('Behat\MinkExtension\ServiceContainer\Driver\DriverFactory');
+    }
+
+    function it_is_named_selenium2()
+    {
+        $this->getDriverName()->shouldReturn('selenium2');
+    }
+
+    function it_supports_javascript()
+    {
+        $this->supportsJavascript()->shouldBe(true);
+    }
+}

spec/Behat/MinkExtension/ServiceContainer/Driver/SeleniumFactorySpec.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace spec\Behat\MinkExtension\ServiceContainer\Driver;
+
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+
+class SeleniumFactorySpec extends ObjectBehavior
+{
+    function it_is_a_driver_factory()
+    {
+        $this->shouldHaveType('Behat\MinkExtension\ServiceContainer\Driver\DriverFactory');
+    }
+
+    function it_is_named_selenium()
+    {
+        $this->getDriverName()->shouldReturn('selenium');
+    }
+
+    function it_supports_javascript()
+    {
+        $this->supportsJavascript()->shouldBe(true);
+    }
+}

spec/Behat/MinkExtension/ServiceContainer/Driver/ZombieFactorySpec.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace spec\Behat\MinkExtension\ServiceContainer\Driver;
+
+use PhpSpec\ObjectBehavior;
+use Prophecy\Argument;
+
+class ZombieFactorySpec extends ObjectBehavior
+{
+    function it_is_a_driver_factory()
+    {
+        $this->shouldHaveType('Behat\MinkExtension\ServiceContainer\Driver\DriverFactory');
+    }
+
+    function it_is_named_zombie()
+    {
+        $this->getDriverName()->shouldReturn('zombie');
+    }
+
+    function it_supports_javascript()
+    {
+        $this->supportsJavascript()->shouldBe(true);
+    }
+}

src/Behat/MinkExtension/Extension.php

@@ -11,6 +11,13 @@
 namespace Behat\MinkExtension;
 
 use Behat\Behat\Context\ServiceContainer\ContextExtension;
+use Behat\MinkExtension\ServiceContainer\Driver\DriverFactory;
+use Behat\MinkExtension\ServiceContainer\Driver\GoutteFactory;
+use Behat\MinkExtension\ServiceContainer\Driver\SahiFactory;
+use Behat\MinkExtension\ServiceContainer\Driver\SaucelabsFactory;
+use Behat\MinkExtension\ServiceContainer\Driver\Selenium2Factory;
+use Behat\MinkExtension\ServiceContainer\Driver\SeleniumFactory;
+use Behat\MinkExtension\ServiceContainer\Driver\ZombieFactory;
 use Behat\Testwork\EventDispatcher\ServiceContainer\EventDispatcherExtension;
 use Behat\Testwork\ServiceContainer\Exception\ProcessingException;
 use Behat\Testwork\ServiceContainer\Extension as ExtensionInterface;
@@ -30,9 +37,28 @@ class Extension implements ExtensionInterface
     const MINK_ID = 'mink';
     const SELECTORS_HANDLER_ID = 'mink.selectors_handler';
 
-    const SESSION_TAG = 'mink.session';
     const SELECTOR_TAG = 'mink.selector';
 
+    /**
+     * @var DriverFactory[]
+     */
+    private $driverFactories = array();
+
+    public function __construct()
+    {
+        $this->registerDriverFactory(new GoutteFactory());
+        $this->registerDriverFactory(new SahiFactory());
+        $this->registerDriverFactory(new SeleniumFactory());
+        $this->registerDriverFactory(new Selenium2Factory());
+        $this->registerDriverFactory(new SaucelabsFactory());
+        $this->registerDriverFactory(new ZombieFactory());
+    }
+
+    public function registerDriverFactory(DriverFactory $driverFactory)
+    {
+        $this->driverFactories[$driverFactory->getDriverName()] = $driverFactory;
+    }
+
     /**
      * {@inheritDoc}
      */
@@ -51,41 +77,17 @@ class Extension implements ExtensionInterface
         $this->loadMink($container);
         $this->loadContextInitializer($container);
         $this->loadSelectorsHandler($container);
+        $this->loadSessions($container, $config);
         $this->loadSessionsListener($container);
 
         if ($config['show_auto']) {
             $this->loadFailureShowListener($container);
         }
 
-        if (isset($config['goutte'])) {
-            $this->loadGoutteSession($container, $config['goutte']);
-            unset($config['goutte']);
-        }
-        if (isset($config['sahi'])) {
-            $this->loadSahiSession($container, $config['sahi']);
-            unset($config['sahi']);
-        }
-        if (isset($config['zombie'])) {
-            $this->loadZombieSession($container, $config['zombie']);
-            unset($config['zombie']);
-        }
-        if (isset($config['selenium'])) {
-            $this->loadSeleniumSession($container, $config['selenium']);
-            unset($config['zombie']);
-        }
-        if (isset($config['selenium2'])) {
-            $this->loadSelenium2Session($container, $config['selenium2']);
-            unset($config['selenium2']);
-        }
-        if (isset($config['saucelabs'])) {
-            $this->loadSaucelabsSession($container, $config['saucelabs']);
-            unset($config['saucelabs']);
-        }
+        unset($config['sessions']);
 
         $container->setParameter('mink.parameters', $config);
         $container->setParameter('mink.base_url', $config['base_url']);
-        $container->setParameter('mink.default_session', $config['default_session']);
-        $container->setParameter('mink.javascript_session', $config['javascript_session']);
         $container->setParameter('mink.browser_name', $config['browser_name']);
     }
 
@@ -103,151 +105,38 @@ class Extension implements ExtensionInterface
                 ->booleanNode('show_auto')->defaultFalse()->end()
                 ->scalarNode('show_cmd')->defaultNull()->end()
                 ->scalarNode('show_tmp_dir')->defaultValue(sys_get_temp_dir())->end()
-                ->scalarNode('default_session')->defaultValue('goutte')->end()
-                ->scalarNode('javascript_session')->defaultValue('selenium2')->end()
+                ->scalarNode('default_session')->defaultNull()->info('Defaults to the first non-javascript session if any, or the first session otherwise')->end()
+                ->scalarNode('javascript_session')->defaultNull()->info('Defaults to the first javascript session if any')->end()
                 ->scalarNode('browser_name')->defaultValue('firefox')->end()
-                ->arrayNode('goutte')
-                    ->children()
-                        ->arrayNode('server_parameters')
-                            ->useAttributeAsKey('key')
-                            ->prototype('variable')->end()
-                        ->end()
-                        ->arrayNode('guzzle_parameters')
-                            ->useAttributeAsKey('key')
-                            ->prototype('variable')->end()
-                            ->validate()
-                                ->always()
-                                ->then(function ($v) {
-                                    $v['redirect.disable'] = true;
-
-                                    return $v;
-                                })
-                            ->end()
-                        ->end()
-                    ->end()
-                ->end()
-                ->arrayNode('sahi')
-                    ->children()
-                        ->scalarNode('sid')->defaultNull()->end()
-                        ->scalarNode('host')->defaultValue('localhost')->end()
-                        ->scalarNode('port')->defaultValue(9999)->end()
-                        ->scalarNode('browser')->defaultNull()->end()
-                        ->scalarNode('limit')->defaultValue(600)->end()
-                    ->end()
-                ->end()
-                ->arrayNode('zombie')
-                    ->children()
-                        ->scalarNode('host')->defaultValue('127.0.0.1')->end()
-                        ->scalarNode('port')->defaultValue(8124)->end()
-                        ->booleanNode('auto_server')->defaultValue(true)->end()
-                        ->scalarNode('node_bin')->defaultValue('node')->end()
-                        ->scalarNode('server_path')->defaultNull()->end()
-                        ->scalarNode('threshold')->defaultValue(2000000)->end()
-                        ->scalarNode('node_modules_path')->defaultValue('')->end()
-                    ->end()
-                ->end()
-                ->arrayNode('selenium')
-                    ->children()
-                        ->scalarNode('host')->defaultValue('127.0.0.1')->end()
-                        ->scalarNode('port')->defaultValue(4444)->end()
-                        ->scalarNode('browser')->defaultValue('*%mink.browser_name%')->end()
-                    ->end()
-                ->end()
-                ->arrayNode('selenium2')
-                    ->children()
-                        ->scalarNode('browser')->defaultValue('%mink.browser_name%')->end()
-                        ->arrayNode('capabilities')
-                            ->addDefaultsIfNotSet()
-                            ->normalizeKeys(false)
-                            ->children()
-                                ->scalarNode('browserName')->defaultValue('firefox')->end()
-                                ->scalarNode('version')->defaultValue('9')->end()
-                                ->scalarNode('platform')->defaultValue('ANY')->end()
-                                ->scalarNode('browserVersion')->defaultValue('9')->end()
-                                ->scalarNode('browser')->defaultValue('firefox')->end()
-                                ->scalarNode('ignoreZoomSetting')->defaultValue('false')->end()
-                                ->scalarNode('name')->defaultValue('Behat Test')->end()
-                                ->scalarNode('deviceOrientation')->defaultValue('portrait')->end()
-                                ->scalarNode('deviceType')->defaultValue('tablet')->end()
-                                ->scalarNode('selenium-version')->defaultValue('2.31.0')->end()
-                                ->scalarNode('max-duration')->defaultValue('300')->end()
-                                ->booleanNode('javascriptEnabled')->end()
-                                ->booleanNode('databaseEnabled')->end()
-                                ->booleanNode('locationContextEnabled')->end()
-                                ->booleanNode('applicationCacheEnabled')->end()
-                                ->booleanNode('browserConnectionEnabled')->end()
-                                ->booleanNode('webStorageEnabled')->end()
-                                ->booleanNode('rotatable')->end()
-                                ->booleanNode('acceptSslCerts')->end()
-                                ->booleanNode('nativeEvents')->end()
-                                ->booleanNode('passed')->end()
-                                ->booleanNode('record-video')->end()
-                                ->booleanNode('record-screenshots')->end()
-                                ->booleanNode('capture-html')->end()
-                                ->booleanNode('disable-popup-handler')->end()
-                                ->arrayNode('proxy')
-                                    ->children()
-                                        ->scalarNode('proxyType')->end()
-                                        ->scalarNode('proxyAuthconfigUrl')->end()
-                                        ->scalarNode('ftpProxy')->end()
-                                        ->scalarNode('httpProxy')->end()
-                                        ->scalarNode('sslProxy')->end()
-                                    ->end()
-                                    ->validate()
-                                        ->ifTrue(function ($v) {
-                                            return empty($v);
-                                        })
-                                        ->thenUnset()
-                                    ->end()
-                                ->end()
-                                ->arrayNode('firefox')
-                                    ->children()
-                                        ->scalarNode('profile')
-                                            ->validate()
-                                                ->ifTrue(function ($v) {
-                                                    return !file_exists($v);
-                                                })
-                                                ->thenInvalid('Cannot find profile zip file %s')
-                                            ->end()
-                                        ->end()
-                                        ->scalarNode('binary')->end()
-                                    ->end()
-                                ->end()
-                                ->arrayNode('chrome')
-                                    ->children()
-                                        ->arrayNode('switches')->prototype('scalar')->end()->end()
-                                        ->scalarNode('binary')->end()
-                                        ->arrayNode('extensions')->prototype('scalar')->end()->end()
-                                    ->end()
-                                ->end()
-                            ->end()
-                        ->end()
-                        ->scalarNode('wd_host')->defaultValue('http://localhost:4444/wd/hub')->end()
-                    ->end()
-                ->end()
-                ->arrayNode('saucelabs')
-                    ->children()
-                        ->scalarNode('username')->defaultValue(getenv('SAUCE_USERNAME'))->end()
-                        ->scalarNode('access_key')->defaultValue(getenv('SAUCE_ACCESS_KEY'))->end()
-                        ->booleanNode('connect')->defaultFalse()->end()
-                        ->scalarNode('browser')->defaultValue('firefox')->end()
-                        ->arrayNode('capabilities')
-                            ->addDefaultsIfNotSet()
-                            ->normalizeKeys(false)
-                            ->children()
-                                ->scalarNode('name')->defaultValue('Behat feature suite')->end()
-                                ->scalarNode('platform')->defaultValue('Linux')->end()
-                                ->scalarNode('version')->defaultValue('21')->end()
-                                ->scalarNode('selenium-version')->defaultValue('2.31.0')->end()
-                                ->scalarNode('max-duration')->defaultValue('300')->end()
-                                ->scalarNode('deviceType')->defaultNull()->end()
-                                ->scalarNode('deviceOrientation')->defaultNull()->end()
-                            ->end()
-                        ->end()
-                    ->end()
-                ->end()
             ->end()
         ->end();
+
+        /** @var ArrayNodeDefinition $sessionsBuilder */
+        $sessionsBuilder = $builder
+            ->children()
+                ->arrayNode('sessions')
+                    ->isRequired()
+                    ->requiresAtLeastOneElement()
+                    ->useAttributeAsKey('name')
+                    ->prototype('array')
+        ;
+
+        foreach ($this->driverFactories as $factory) {
+            $factoryNode = $sessionsBuilder->children()->arrayNode($factory->getDriverName())->canBeUnset();
+
+            $factory->configure($factoryNode);
+        }
+
+        $sessionsBuilder
+            ->validate()
+                ->ifTrue(function ($v) {return count($v) > 1;})
+                ->thenInvalid('You cannot set multiple driver types for the same session')
+            ->end()
+            ->validate()
+                ->ifTrue(function ($v) {return count($v) === 0;})
+                ->thenInvalid('You must set a driver definition for the session.')
+            ->end()
+        ;
     }
 
     /**
@@ -270,7 +159,6 @@ class Extension implements ExtensionInterface
      */
     public function process(ContainerBuilder $container)
     {
-        $this->processSessions($container);
         $this->processSelectors($container);
     }
 
@@ -302,11 +190,49 @@ class Extension implements ExtensionInterface
         $container->setDefinition(self::SELECTOR_TAG . '.named', $namedSelectorDefinition);
     }
 
+    private function loadSessions(ContainerBuilder $container, array $config)
+    {
+        $defaultSession = $config['default_session'];
+        $javascriptSession = $config['javascript_session'];
+        $javascriptSessions = $nonJavascriptSessions = array();
+
+        $minkDefinition = $container->getDefinition(self::MINK_ID);
+
+        foreach ($config['sessions'] as $name => $session) {
+            $driver = key($session);
+            $factory = $this->driverFactories[$driver];
+
+            $definition = new Definition('Behat\Mink\Session', array(
+                $factory->buildDriver($session[$driver]),
+                new Reference(self::SELECTORS_HANDLER_ID),
+            ));
+            $minkDefinition->addMethodCall('registerSession', array($name, $definition));
+
+            if ($factory->supportsJavascript()) {
+                $javascriptSessions[] = $name;
+            } else {
+                $nonJavascriptSessions[] = $name;
+            }
+        }
+
+        if (null === $javascriptSession && !empty($javascriptSessions)) {
+            $javascriptSession = $javascriptSessions[0];
+        }
+
+        if (null === $defaultSession) {
+            $defaultSession = !empty($nonJavascriptSessions) ? $nonJavascriptSessions[0] : $javascriptSessions[0];
+        }
+
+        $container->setParameter('mink.default_session', $defaultSession);
+        $container->setParameter('mink.javascript_session', $javascriptSession);
+    }
+
     private function loadSessionsListener(ContainerBuilder $container)
     {
         $definition = new Definition('Behat\MinkExtension\Listener\SessionsListener', array(
             new Reference(self::MINK_ID),
-            '%mink.parameters%',
+            '%mink.default_session%',
+            '%mink.javascript_session%',
         ));
         $definition->addTag(EventDispatcherExtension::SUBSCRIBER_TAG, array('priority' => 0));
         $container->setDefinition('mink.listener.sessions', $definition);
@@ -322,173 +248,6 @@ class Extension implements ExtensionInterface
         $container->setDefinition('mink.listener.failure_show', $definition);
     }
 
-    private function loadGoutteSession(ContainerBuilder $container, array $config)
-    {
-        if (!class_exists('Behat\Mink\Driver\GoutteDriver')) {
-            throw new \RuntimeException(
-                'Install MinkGoutteDriver in order to activate goutte session.'
-            );
-        }
-
-        $clientDefinition = new Definition('Behat\Mink\Driver\Goutte\Client', array(
-            $config['server_parameters'],
-        ));
-        $clientDefinition->addMethodCall('setClient', array(
-            new Definition('Guzzle\Http\Client', array(
-                null,
-                $config['guzzle_parameters'],
-            )),
-        ));
-
-        $driverDefinition = new Definition('Behat\Mink\Driver\GoutteDriver', array(
-            $clientDefinition,
-        ));
-        $this->loadSession($container, $driverDefinition, 'goutte');
-    }
-
-    private function loadSahiSession(ContainerBuilder $container, array $config)
-    {
-        if (!class_exists('Behat\Mink\Driver\SahiDriver')) {
-            throw new \RuntimeException(
-                'Install MinkSahiDriver in order to activate sahi session.'
-            );
-        }
-
-        $driverDefinition = new Definition('Behat\Mink\Driver\SahiDriver', array(
-            '%mink.browser_name%',
-            new Definition('Behat\SahiClient\Client', array(
-                new Definition('Behat\SahiClient\Connection', array(
-                    $config['sid'],
-                    $config['host'],
-                    $config['port'],
-                    $config['browser'],
-                    $config['limit'],
-                )),
-            )),
-        ));
-        $this->loadSession($container, $driverDefinition, 'sahi');
-    }
-
-    private function loadZombieSession(ContainerBuilder $container, array $config)
-    {
-        if (!class_exists('Behat\Mink\Driver\ZombieDriver')) {
-            throw new \RuntimeException(
-                'Install MinkZombieDriver in order to activate zombie session.'
-            );
-        }
-
-        $driverDefinition = new Definition('Behat\Mink\Driver\ZombieDriver', array(
-            new Definition('Behat\Mink\Driver\NodeJS\Server\ZombieServer', array(
-                $config['host'],
-                $config['port'],
-                $config['node_bin'],
-                $config['server_path'],
-                $config['threshold'],
-                $config['node_modules_path'],
-            )),
-            new Definition('Behat\Mink\Driver\NodeJS\Connection', array(
-                $config['host'],
-                $config['port'],
-            )),
-            $config['auto_server'],
-        ));
-        $this->loadSession($container, $driverDefinition, 'zombie');
-    }
-
-    private function loadSeleniumSession(ContainerBuilder $container, array $config)
-    {
-        if (!class_exists('Behat\Mink\Driver\SeleniumDriver')) {
-            throw new \RuntimeException(
-                'Install MinkSeleniumDriver in order to activate selenium session.'
-            );
-        }
-
-        $driverDefinition = new Definition('Behat\Mink\Driver\SeleniumDriver', array(
-            $config['browser'],
-            '%mink.base_url%',
-            new Definition('Selenium\Client', array(
-                $config['host'],
-                $config['port'],
-            )),
-        ));
-        $this->loadSession($container, $driverDefinition, 'selenium');
-    }
-
-    private function loadSelenium2Session(ContainerBuilder $container, array $config)
-    {
-        if (!class_exists('Behat\Mink\Driver\Selenium2Driver')) {
-            throw new \RuntimeException(
-                'Install MinkSelenium2Driver in order to activate selenium2 session.'
-            );
-        }
-
-        $driverDefinition = new Definition('Behat\Mink\Driver\Selenium2Driver', array(
-            $config['browser'],
-            $config['capabilities'],
-            $config['wd_host'],
-        ));
-        $this->loadSession($container, $driverDefinition, 'selenium2');
-    }
-
-    private function loadSaucelabsSession(ContainerBuilder $container, array $config)
-    {
-        if (!class_exists('Behat\Mink\Driver\Selenium2Driver')) {
-            throw new \RuntimeException(
-                'Install MinkSelenium2Driver in order to activate saucelabs session.'
-            );
-        }
-        $capabilities = $config['capabilities'];
-        $capabilities['tags'] = array(php_uname('n'), 'PHP '.phpversion());
-
-        if (getenv('TRAVIS_JOB_NUMBER')) {
-            $capabilities['tunnel-identifier'] = getenv('TRAVIS_JOB_NUMBER');
-            $capabilities['build'] = getenv('TRAVIS_BUILD_NUMBER');
-            $capabilities['tags'] = array('Travis-CI', 'PHP '.phpversion());
-        }
-
-        $host = 'ondemand.saucelabs.com';
-        if ($config['connect']) {
-            $host = 'localhost:4445';
-        }
-
-        $driverDefinition = new Definition('Behat\Mink\Driver\Selenium2Driver', array(
-            $config['browser'],
-            $capabilities,
-            sprintf('%s:%s@%s/wd/hub', $config['username'], $config['access_key'], $host),
-        ));
-        $this->loadSession($container, $driverDefinition, 'saucelabs');
-    }
-
-    private function loadSession(ContainerBuilder $container, Definition $driverDefinition, $alias)
-    {
-        $definition = new Definition('Behat\Mink\Session', array(
-            $driverDefinition,
-            new Reference(self::SELECTORS_HANDLER_ID),
-        ));
-        $definition->addTag(self::SESSION_TAG, array('alias' => $alias));
-        $container->setDefinition(self::SESSION_TAG . '.' . $alias, $definition);
-    }
-
-    private function processSessions(ContainerBuilder $container)
-    {
-        $handlerDefinition = $container->getDefinition(self::MINK_ID);
-
-        foreach ($container->findTaggedServiceIds(self::SESSION_TAG) as $id => $tags) {
-            foreach ($tags as $tag) {
-                if (!isset($tag['alias'])) {
-                    throw new ProcessingException(sprintf(
-                        'All `%s` tags should have an `alias` attribute, but `%s` service has none.',
-                        $tag,
-                        $id
-                    ));
-                }
-                $handlerDefinition->addMethodCall(
-                    'registerSession', array($tag['alias'], new Reference($id))
-                );
-            }
-        }
-    }
-
     private function processSelectors(ContainerBuilder $container)
     {
         $handlerDefinition = $container->getDefinition(self::SELECTORS_HANDLER_ID);

src/Behat/MinkExtension/Listener/SessionsListener.php

@@ -14,6 +14,7 @@ use Behat\Behat\Tester\Event\AbstractScenarioTested;
 use Behat\Behat\Tester\Event\ExampleTested;
 use Behat\Behat\Tester\Event\ScenarioTested;
 use Behat\Mink\Mink;
+use Behat\Testwork\ServiceContainer\Exception\ProcessingException;
 use Behat\Testwork\Tester\Event\ExerciseCompleted;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
@@ -26,18 +27,21 @@ use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 class SessionsListener implements EventSubscriberInterface
 {
     private $mink;
-    private $parameters;
+    private $defaultSession;
+    private $javascriptSession;
 
     /**
      * Initializes initializer.
      *
      * @param Mink        $mink
-     * @param array $parameters
+     * @param string      $defaultSession
+     * @param string|null $javascriptSession
      */
-    public function __construct(Mink $mink, array $parameters)
+    public function __construct(Mink $mink, $defaultSession, $javascriptSession)
     {
         $this->mink              = $mink;
-        $this->parameters = $parameters;
+        $this->defaultSession    = $defaultSession;
+        $this->javascriptSession = $javascriptSession;
     }
 
     /**
@@ -64,16 +68,22 @@ class SessionsListener implements EventSubscriberInterface
      * instead of just soft-resetting them
      *
      * @param AbstractScenarioTested $event
+     *
+     * @throws ProcessingException when the @javascript tag is used without a javascript session
      */
     public function prepareDefaultMinkSession(AbstractScenarioTested $event)
     {
         $scenario = $event->getScenario();
         $feature  = $event->getFeature();
-        $session  = $this->parameters['default_session'];
+        $session  = $this->defaultSession;
 
         foreach (array_merge($feature->getTags(), $scenario->getTags()) as $tag) {
             if ('javascript' === $tag) {
-                $session = $this->parameters['javascript_session'];
+                if (null === $this->javascriptSession) {
+                    throw new ProcessingException('The @javascript tag cannot be used without enabling a javascript session');
+                }
+
+                $session = $this->javascriptSession;
             } elseif (preg_match('/^mink\:(.+)/', $tag, $matches)) {
                 $session = $matches[1];
             }

src/Behat/MinkExtension/ServiceContainer/Driver/DriverFactory.php

@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of the Behat MinkExtension.
+ * (c) Konstantin Kudryashov <ever.zet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Behat\MinkExtension\ServiceContainer\Driver;
+
+use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
+use Symfony\Component\DependencyInjection\Definition;
+
+/**
+ * @author Christophe Coevoet <stof@notk.org>
+ */
+interface DriverFactory
+{
+    /**
+     * Gets the name of the driver being configured.
+     *
+     * This will be the key of the configuration for the driver.
+     *
+     * @return string
+     */
+    public function getDriverName();
+
+    /**
+     * Defines whether a session using this driver is eligible as default javascript session
+     *
+     * @return boolean
+     */
+    public function supportsJavascript();
+
+    /**
+     * Setups configuration for the driver factory.
+     *
+     * @param ArrayNodeDefinition $builder
+     */
+    public function configure(ArrayNodeDefinition $builder);
+
+    /**
+     * Builds the service definition for the driver.
+     *
+     * @param array $config
+     *
+     * @return Definition
+     */
+    public function buildDriver(array $config);
+}

src/Behat/MinkExtension/ServiceContainer/Driver/GoutteFactory.php

@@ -0,0 +1,89 @@
+<?php
+
+/*
+ * This file is part of the Behat MinkExtension.
+ * (c) Konstantin Kudryashov <ever.zet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Behat\MinkExtension\ServiceContainer\Driver;
+
+use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
+use Symfony\Component\DependencyInjection\Definition;
+
+/**
+ * @author Christophe Coevoet <stof@notk.org>
+ */
+class GoutteFactory implements DriverFactory
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getDriverName()
+    {
+        return 'goutte';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsJavascript()
+    {
+        return false;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function configure(ArrayNodeDefinition $builder)
+    {
+        $builder
+            ->children()
+                ->arrayNode('server_parameters')
+                    ->useAttributeAsKey('key')
+                    ->prototype('variable')->end()
+                ->end()
+                ->arrayNode('guzzle_parameters')
+                    ->useAttributeAsKey('key')
+                    ->prototype('variable')->end()
+                    ->validate()
+                        ->always()
+                        ->then(function ($v) {
+                            $v['redirect.disable'] = true;
+
+                            return $v;
+                        })
+                    ->end()
+                ->end()
+            ->end()
+        ;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function buildDriver(array $config)
+    {
+        if (!class_exists('Behat\Mink\Driver\GoutteDriver')) {
+            throw new \RuntimeException(
+                'Install MinkGoutteDriver in order to use goutte driver.'
+            );
+        }
+
+        $clientDefinition = new Definition('Behat\Mink\Driver\Goutte\Client', array(
+            $config['server_parameters'],
+        ));
+        $clientDefinition->addMethodCall('setClient', array(
+            new Definition('Guzzle\Http\Client', array(
+                null,
+                $config['guzzle_parameters'],
+            )),
+        ));
+
+        return new Definition('Behat\Mink\Driver\GoutteDriver', array(
+            $clientDefinition,
+        ));
+    }
+}

src/Behat/MinkExtension/ServiceContainer/Driver/SahiFactory.php

@@ -0,0 +1,74 @@
+<?php
+
+/*
+ * This file is part of the Behat MinkExtension.
+ * (c) Konstantin Kudryashov <ever.zet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Behat\MinkExtension\ServiceContainer\Driver;
+
+use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
+use Symfony\Component\DependencyInjection\Definition;
+
+class SahiFactory implements DriverFactory
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getDriverName()
+    {
+        return 'sahi';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsJavascript()
+    {
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function configure(ArrayNodeDefinition $builder)
+    {
+        $builder
+            ->children()
+                ->scalarNode('sid')->defaultNull()->end()
+                ->scalarNode('host')->defaultValue('localhost')->end()
+                ->scalarNode('port')->defaultValue(9999)->end()
+                ->scalarNode('browser')->defaultNull()->end()
+                ->scalarNode('limit')->defaultValue(600)->end()
+            ->end()
+        ;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function buildDriver(array $config)
+    {
+        if (!class_exists('Behat\Mink\Driver\SahiDriver')) {
+            throw new \RuntimeException(
+                'Install MinkSahiDriver in order to use sahi driver.'
+            );
+        }
+
+        return new Definition('Behat\Mink\Driver\SahiDriver', array(
+            '%mink.browser_name%',
+            new Definition('Behat\SahiClient\Client', array(
+                new Definition('Behat\SahiClient\Connection', array(
+                    $config['sid'],
+                    $config['host'],
+                    $config['port'],
+                    $config['browser'],
+                    $config['limit'],
+                )),
+            )),
+        ));
+    }
+}

src/Behat/MinkExtension/ServiceContainer/Driver/SaucelabsFactory.php

@@ -0,0 +1,92 @@
+<?php
+
+/*
+ * This file is part of the Behat MinkExtension.
+ * (c) Konstantin Kudryashov <ever.zet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Behat\MinkExtension\ServiceContainer\Driver;
+
+use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
+use Symfony\Component\DependencyInjection\Definition;
+
+class SaucelabsFactory implements DriverFactory
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getDriverName()
+    {
+        return 'saucelabs';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsJavascript()
+    {
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function configure(ArrayNodeDefinition $builder)
+    {
+        $builder
+            ->children()
+                ->scalarNode('username')->defaultValue(getenv('SAUCE_USERNAME'))->end()
+                ->scalarNode('access_key')->defaultValue(getenv('SAUCE_ACCESS_KEY'))->end()
+                ->booleanNode('connect')->defaultFalse()->end()
+                ->scalarNode('browser')->defaultValue('firefox')->end()
+                ->arrayNode('capabilities')
+                    ->addDefaultsIfNotSet()
+                    ->normalizeKeys(false)
+                    ->children()
+                        ->scalarNode('name')->defaultValue('Behat feature suite')->end()
+                        ->scalarNode('platform')->defaultValue('Linux')->end()
+                        ->scalarNode('version')->defaultValue('21')->end()
+                        ->scalarNode('selenium-version')->defaultValue('2.31.0')->end()
+                        ->scalarNode('max-duration')->defaultValue('300')->end()
+                        ->scalarNode('deviceType')->defaultNull()->end()
+                        ->scalarNode('deviceOrientation')->defaultNull()->end()
+                    ->end()
+                ->end()
+            ->end()
+        ;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function buildDriver(array $config)
+    {
+        if (!class_exists('Behat\Mink\Driver\Selenium2Driver')) {
+            throw new \RuntimeException(
+                'Install MinkSelenium2Driver in order to use saucelabs driver.'
+            );
+        }
+        $capabilities = $config['capabilities'];
+        $capabilities['tags'] = array(php_uname('n'), 'PHP '.phpversion());
+
+        if (getenv('TRAVIS_JOB_NUMBER')) {
+            $capabilities['tunnel-identifier'] = getenv('TRAVIS_JOB_NUMBER');
+            $capabilities['build'] = getenv('TRAVIS_BUILD_NUMBER');
+            $capabilities['tags'] = array('Travis-CI', 'PHP '.phpversion());
+        }
+
+        $host = 'ondemand.saucelabs.com';
+        if ($config['connect']) {
+            $host = 'localhost:4445';
+        }
+
+        return new Definition('Behat\Mink\Driver\Selenium2Driver', array(
+            $config['browser'],
+            $capabilities,
+            sprintf('%s:%s@%s/wd/hub', $config['username'], $config['access_key'], $host),
+        ));
+    }
+}

src/Behat/MinkExtension/ServiceContainer/Driver/Selenium2Factory.php

@@ -0,0 +1,130 @@
+<?php
+
+/*
+ * This file is part of the Behat MinkExtension.
+ * (c) Konstantin Kudryashov <ever.zet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Behat\MinkExtension\ServiceContainer\Driver;
+
+use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
+use Symfony\Component\DependencyInjection\Definition;
+
+class Selenium2Factory implements DriverFactory
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getDriverName()
+    {
+        return 'selenium2';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsJavascript()
+    {
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function configure(ArrayNodeDefinition $builder)
+    {
+        $builder
+            ->children()
+                ->scalarNode('browser')->defaultValue('%mink.browser_name%')->end()
+                ->arrayNode('capabilities')
+                    ->addDefaultsIfNotSet()
+                    ->normalizeKeys(false)
+                    ->children()
+                        ->scalarNode('browserName')->defaultValue('firefox')->end()
+                        ->scalarNode('version')->defaultValue('9')->end()
+                        ->scalarNode('platform')->defaultValue('ANY')->end()
+                        ->scalarNode('browserVersion')->defaultValue('9')->end()
+                        ->scalarNode('browser')->defaultValue('firefox')->end()
+                        ->scalarNode('ignoreZoomSetting')->defaultValue('false')->end()
+                        ->scalarNode('name')->defaultValue('Behat Test')->end()
+                        ->scalarNode('deviceOrientation')->defaultValue('portrait')->end()
+                        ->scalarNode('deviceType')->defaultValue('tablet')->end()
+                        ->scalarNode('selenium-version')->defaultValue('2.31.0')->end()
+                        ->scalarNode('max-duration')->defaultValue('300')->end()
+                        ->booleanNode('javascriptEnabled')->end()
+                        ->booleanNode('databaseEnabled')->end()
+                        ->booleanNode('locationContextEnabled')->end()
+                        ->booleanNode('applicationCacheEnabled')->end()
+                        ->booleanNode('browserConnectionEnabled')->end()
+                        ->booleanNode('webStorageEnabled')->end()
+                        ->booleanNode('rotatable')->end()
+                        ->booleanNode('acceptSslCerts')->end()
+                        ->booleanNode('nativeEvents')->end()
+                        ->booleanNode('passed')->end()
+                        ->booleanNode('record-video')->end()
+                        ->booleanNode('record-screenshots')->end()
+                        ->booleanNode('capture-html')->end()
+                        ->booleanNode('disable-popup-handler')->end()
+                        ->arrayNode('proxy')
+                            ->children()
+                                ->scalarNode('proxyType')->end()
+                                ->scalarNode('proxyAuthconfigUrl')->end()
+                                ->scalarNode('ftpProxy')->end()
+                                ->scalarNode('httpProxy')->end()
+                                ->scalarNode('sslProxy')->end()
+                            ->end()
+                            ->validate()
+                                ->ifTrue(function ($v) {
+                                    return empty($v);
+                                })
+                                ->thenUnset()
+                            ->end()
+                        ->end()
+                        ->arrayNode('firefox')
+                            ->children()
+                                ->scalarNode('profile')
+                                    ->validate()
+                                        ->ifTrue(function ($v) {
+                                            return !file_exists($v);
+                                        })
+                                        ->thenInvalid('Cannot find profile zip file %s')
+                                    ->end()
+                                ->end()
+                                ->scalarNode('binary')->end()
+                            ->end()
+                        ->end()
+                        ->arrayNode('chrome')
+                            ->children()
+                                ->arrayNode('switches')->prototype('scalar')->end()->end()
+                                ->scalarNode('binary')->end()
+                                ->arrayNode('extensions')->prototype('scalar')->end()->end()
+                            ->end()
+                        ->end()
+                    ->end()
+                ->end()
+                ->scalarNode('wd_host')->defaultValue('http://localhost:4444/wd/hub')->end()
+            ->end()
+        ;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function buildDriver(array $config)
+    {
+        if (!class_exists('Behat\Mink\Driver\Selenium2Driver')) {
+            throw new \RuntimeException(
+                'Install MinkSelenium2Driver in order to use selenium2 driver.'
+            );
+        }
+
+        return new Definition('Behat\Mink\Driver\Selenium2Driver', array(
+            $config['browser'],
+            $config['capabilities'],
+            $config['wd_host'],
+        ));
+    }
+}

src/Behat/MinkExtension/ServiceContainer/Driver/SeleniumFactory.php

@@ -0,0 +1,68 @@
+<?php
+
+/*
+ * This file is part of the Behat MinkExtension.
+ * (c) Konstantin Kudryashov <ever.zet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Behat\MinkExtension\ServiceContainer\Driver;
+
+use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
+use Symfony\Component\DependencyInjection\Definition;
+
+class SeleniumFactory implements DriverFactory
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getDriverName()
+    {
+        return 'selenium';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsJavascript()
+    {
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function configure(ArrayNodeDefinition $builder)
+    {
+        $builder
+            ->children()
+                ->scalarNode('host')->defaultValue('127.0.0.1')->end()
+                ->scalarNode('port')->defaultValue(4444)->end()
+                ->scalarNode('browser')->defaultValue('*%mink.browser_name%')->end()
+            ->end()
+        ;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function buildDriver(array $config)
+    {
+        if (!class_exists('Behat\Mink\Driver\SeleniumDriver')) {
+            throw new \RuntimeException(
+                'Install MinkSeleniumDriver in order to activate selenium session.'
+            );
+        }
+
+        return new Definition('Behat\Mink\Driver\SeleniumDriver', array(
+            $config['browser'],
+            '%mink.base_url%',
+            new Definition('Selenium\Client', array(
+                $config['host'],
+                $config['port'],
+            )),
+        ));
+    }
+}

src/Behat/MinkExtension/ServiceContainer/Driver/ZombieFactory.php

@@ -0,0 +1,79 @@
+<?php
+
+/*
+ * This file is part of the Behat MinkExtension.
+ * (c) Konstantin Kudryashov <ever.zet@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Behat\MinkExtension\ServiceContainer\Driver;
+
+use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
+use Symfony\Component\DependencyInjection\Definition;
+
+class ZombieFactory implements DriverFactory
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getDriverName()
+    {
+        return 'zombie';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function supportsJavascript()
+    {
+        return true;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function configure(ArrayNodeDefinition $builder)
+    {
+        $builder
+            ->children()
+                ->scalarNode('host')->defaultValue('127.0.0.1')->end()
+                ->scalarNode('port')->defaultValue(8124)->end()
+                ->booleanNode('auto_server')->defaultTrue()->end()
+                ->scalarNode('node_bin')->defaultValue('node')->end()
+                ->scalarNode('server_path')->defaultNull()->end()
+                ->scalarNode('threshold')->defaultValue(2000000)->end()
+                ->scalarNode('node_modules_path')->defaultValue('')->end()
+            ->end()
+        ;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function buildDriver(array $config)
+    {
+        if (!class_exists('Behat\Mink\Driver\ZombieDriver')) {
+            throw new \RuntimeException(
+                'Install MinkZombieDriver in order to use zombie driver.'
+            );
+        }
+
+        return new Definition('Behat\Mink\Driver\ZombieDriver', array(
+            new Definition('Behat\Mink\Driver\NodeJS\Server\ZombieServer', array(
+                $config['host'],
+                $config['port'],
+                $config['node_bin'],
+                $config['server_path'],
+                $config['threshold'],
+                $config['node_modules_path'],
+            )),
+            new Definition('Behat\Mink\Driver\NodeJS\Connection', array(
+                $config['host'],
+                $config['port'],
+            )),
+            $config['auto_server'],
+        ));
+    }
+}