Using correct assertion instead of a callable (does not work with hhvm)

tests/OcraServiceManagerTest/ServiceFactory/EventManagerFactoryTest.php

@@ -40,9 +40,7 @@ public function testCreateService()
         $listenerMock
             ->expects($this->once())
             ->method('attach')
-            ->with($this->callback(function ($eventManager) {
-                return $eventManager instanceof EventManagerInterface;
-            }));
+            ->with($this->isInstanceOf('Zend\EventManager\EventManagerInterface'));
         $serviceLocator
             ->expects($this->any())
             ->method('get')