Set event subscriber priority for failure events

[yesdevnull]

Problem

In a module I want to handle failures and see whether fail-fast is enabled or not. For example, extending the Doctrine2 module to not cleanup when fail-fast is enabled so the state of the Doctrine data store can be introspected after a failure has occurred.

As it stands, modules catch Events::TEST_FAIL and Events::TEST_ERROR before the FailFast subscriber because modules are configured first.

A simple dump of the EventDispatcher's set of listeners for test.fail shows:

    "test.fail" => array:4 [
      0 => Codeception\Subscriber\Module::failed(FailEvent $event): void^ {#28422
        returnType: "void"
        this: Codeception\Subscriber\Module^ {#308}
      }
      1 => Codeception\Subscriber\FailFast::stopOnFail(TestEvent $e): void^ {#28416
        returnType: "void"
        this: Codeception\Subscriber\FailFast {#318 …}
      }
      2 => Codeception\Extension\Logger::testFail(FailEvent $event): void^ {#28410
        returnType: "void"
        this: Codeception\Extension\Logger^ {#231}
      }
      3 => Codeception\Subscriber\Console::testFail(FailEvent $event): void^ {#28411
        returnType: "void"
        this: Codeception\Subscriber\Console {#320 …}
      }
    ]

Solution

As event subscribers have been configured without a priority the order is determined by the order in which they are added to the event dispatcher's subscriber. As per the Symfony docs a priority can be set for event subscribers.

By setting a higher positive number we ensure FailFast is called first when the Events::TEST_FAIL and Events::TEST_ERROR events are triggered.

With my change I can ensure that the ResultAggregator has been configured to stop in the event that fail-fast has been enabled, and in turn I can see that in my own Codeception modules and handle it appropriately.