POC: implement cross-context communication for Behat-3

behat.yml

default:

    extensions:
        Kaliop\Behat\KToolsExtension: ~

EventListener.php

<?php

namespace Kaliop\Behat\KToolsExtension\Listener;

use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Behat\Behat\EventDispatcher\Event\ScenarioTested;
use Behat\Behat\EventDispatcher\Event\OutlineTested;
use Behat\Behat\EventDispatcher\Event\ScenarioLikeTested;
use Kaliop\Behat\KToolsExtension\Context\SharedContext;

/**
 * Will hold all the necessary event listeners
 */
class EventListener implements EventSubscriberInterface
{
    protected $sharedContext;

    /**
     * @param SharedContext $sharedContext
     */
    public function __construct($sharedContext)
    {
        $this->sharedContext = $sharedContext;
    }

    /**
     * @return array
     */
    public static function getSubscribedEvents()
    {
        return array(
            // these we call after either a single scenario or a scenario-with-examples has finished
            ScenarioTested::BEFORE_TEARDOWN => array('resetSharedContexts', -10),
            OutlineTested::BEFORE_TEARDOWN => array('resetSharedContexts', -10),
        );
    }

    public function resetSharedContexts()
    {
        $this->sharedContext->resetContexts();
    }
}

services.yml

parameters:
    kaliop.ktools_extension.context.initializer.class: Kaliop\Behat\KToolsExtension\Context\Initializer\ShareableContextInitializer
    kaliop.ktools_extension.sharedcontext.container.class: Kaliop\Behat\KToolsExtension\Context\SharedContextContainer
    kaliop.ktools_extension.event.listener.class: Kaliop\Behat\KToolsExtension\Listener\EventListener

services:

    kaliop.ktools_extension.sharedcontext.container:
        class: "%kaliop.ktools_extension.sharedcontext.container.class%"

    kaliop.ktools_extension.context.initializer:
        class: "%kaliop.ktools_extension.context.initializer.class%"
        arguments: [@kaliop.ktools_extension.sharedcontext.container]
        tags:
            - { name: context.initializer }

    kaliop.ktools_extension.event.listener:
        class: "%kaliop.ktools_extension.event.listener.class%"
        arguments: [@kaliop.ktools_extension.sharedcontext.container]
        tags:
            - { name: event_dispatcher.subscriber }

ShareableContext.php

<?php

namespace Kaliop\Behat\KToolsExtension\Context;

interface ShareableContext
{
    /**
     * @param callable $shareCallable
     *
     * Implementors just need to execute call_user_func($shareCallable, $this);
     */
    public function shareContext($shareCallable);
}

ShareableContextInitializer.php

<?php

namespace Kaliop\Behat\KToolsExtension\Context\Initializer;

use Behat\Behat\Context\Context;
use Behat\Behat\Context\Initializer\ContextInitializer;
use Kaliop\Behat\KToolsExtension\Context\ShareableContext;
use Kaliop\Behat\KToolsExtension\Context\SharedContextAwareContext;

class ShareableContextInitializer implements ContextInitializer
{
    protected $sharedContextContainer = null;

    /**
     * @param $sharedContextContainer
     */
    public function __construct($sharedContextContainer)
    {
        $this->sharedContextContainer = $sharedContextContainer;
    }

    /**
     * @param Context $context
     */
    public function initializeContext(Context $context)
    {
        if ($context instanceof ShareableContext) {
            $context->shareContext(array($this->sharedContextContainer, 'shareContext'));
        }
        if ($context instanceof SharedContextAwareContext) {
            $context->setSharedContextContainer($this->sharedContextContainer);
        }
    }
}

SharedContextAwareContext.php

<?php

namespace Kaliop\Behat\KToolsExtension\Context;

use Kaliop\Behat\KToolsExtension\Context\SharedContextContainer;

interface SharedContextAwareContext
{
    /**
     * @param SharedContextContainer $sharedContextContainer
     */
    public function setSharedContextContainer($sharedContextContainer);
}

SharedContextContainer.php

<?php

namespace Kaliop\Behat\KToolsExtension\Context;

use Behat\Behat\Context\Context;

/**
 * Implements a 'singleton' pattern to allow communication between the different Contexts in a feature.
 * In practice this class will hold instances of contexts - one instance per class.
 * Contexts who want to be shared just need to implement the ShareableContext interface.
 * To grab a hold on an instance of this class, use an appropriate Symfony service
 *
 * @todo implement an interface
 * @todo allow usage of fully qualified classnames as context identifiers (based eg. on a bool flag passed to constructor)
 */
class SharedContextContainer
{
    protected static $contexts = array();

    public function shareContext(Context $context)
    {
        $className = get_class($context);
        $className = end(explode('\\', $className));
        static::$contexts[$className] = $context;
    }

    /**
     * @param string $name name (class) of context
     * @return Context
     */
    public function getContext($name)
    {
        if(!isset(static::$contexts[$name]))
            throw new \RuntimeException("No context of type '$name' has been shared");
        return static::$contexts[$name];
    }

    public function resetContexts()
    {
        static::$contexts = array();
    }
}