Merge pull request #65 from stof/context_communication

Add a cookbook about accessing contexts from each other

cookbooks/context_communication.rst

@@ -0,0 +1,37 @@
+Accessing contexts from each other
+==================================
+
+When splitting the definitions in multiple contexts, it might be useful to
+access a context from another one. This is particularly useful when migrating
+from Behat 2.x to replace subcontexts.
+
+Behat allows to access the environment in doc:`hooks </guides/3.hooks>`,
+so other contexts can be retrieved using a ``BeforeScenario`` hook:
+
+.. code-block:: php
+
+    use Behat\Behat\Context\Context;
+    use Behat\Behat\Hook\Scope\BeforeScenarioScope;
+
+    class FeatureContext implements Context
+    {
+        /** @var \Behat\MinkExtension\Context\MinkContext */
+        private $minkContext;
+
+        /** @BeforeScenario */
+        public function gatherContexts(BeforeScenarioScope $scope)
+        {
+            $environment = $scope->getEnvironment();
+
+            $this->minkContext = $environment->getContext('Behat\MinkExtension\Context\MinkContext');
+        }
+    }
+
+.. caution::
+
+    Circular references in context objects would prevent the PHP reference
+    counting from collecting contexts at the end of each scenarios, forcing
+    to wait for the garbage collector to run. This would increase the memory
+    usage of your Behat run. To prevent that, it is better to avoid storing
+    the environment itself in your context classes. It is also better to
+    avoid creating circular references between different contexts.

index.rst

@@ -88,6 +88,7 @@ Learn specific solutions for specific needs:
     :maxdepth: 1
 
     cookbooks/1.symfony2_integration
+    cookbooks/context_communication
 
 More about Behaviour Driven Development
 ---------------------------------------