Ensure that we get the parent locator

Some tests are injecting the plugin manager as the service locator, when, in
fact, the two instances should be discretely different. This patch ensures the
tests continue to pass by updating `setServiceLocator()` to test if the instance
is a plugin manager. If it is, it pulls the parent context and uses that
instead.

src/Helper/Navigation/AbstractHelper.php

@@ -11,6 +11,7 @@
 
 use Interop\Container\ContainerInterface;
 use RecursiveIteratorIterator;
+use ReflectionProperty;
 use Zend\EventManager\EventManager;
 use Zend\EventManager\EventManagerAwareInterface;
 use Zend\EventManager\EventManagerInterface;
@@ -19,6 +20,7 @@
 use Zend\Navigation;
 use Zend\Navigation\Page\AbstractPage;
 use Zend\Permissions\Acl;
+use Zend\ServiceManager\AbstractPluginManager;
 use Zend\View;
 use Zend\View\Exception;
 
@@ -753,6 +755,26 @@ public function hasRole()
      */
     public function setServiceLocator(ContainerInterface $serviceLocator)
     {
+        // If we are provided a plugin manager, we should pull the parent
+        // context from it.
+        // @todo We should update tests and code to ensure that this situation
+        //       doesn't happen in the future.
+        if ($serviceLocator instanceof AbstractPluginManager
+            && ! method_exists($serviceLocator, 'configure')
+            && $serviceLocator->getServiceLocator()
+        ) {
+            $serviceLocator = $serviceLocator->getServiceLocator();
+        }
+
+        // v3 variant; likely won't be needed.
+        if ($serviceLocator instanceof AbstractPluginManager
+            && method_exists($serviceLocator, 'configure')
+        ) {
+            $r = new ReflectionProperty($serviceLocator, 'creationContext');
+            $r->setAccessible(true);
+            $serviceLocator = $r->getValue($serviceLocator);
+        }
+
         $this->serviceLocator = $serviceLocator;
         return $this;
     }