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Created EventListenerIntrospectionTrait
This trait is intended to provide a forwards-compatibility shim for use when testing event listener registration. Methods mimic some of the functionality already in v2 (via `getEvents()` and `getListeners()`), but in such a way as to allow common behavior when testing the two versions. In particular, it provides the assertion method `assertListenerAtPriority()`, allowing developers to test that a listener was registered for the specified event at the specified priority; this is useful when testing attachment by aggregates or of default listeners.
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‎src/Test/EventListenerIntrospectionTrait.php

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<?php
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/**
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* Zend Framework (http://framework.zend.com/)
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*
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* @link http://github.com/zendframework/zend-eventmanager for the canonical source repository
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* @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
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* @license https://github.com/zendframework/zend-eventmanager/blob/master/LICENSE.md
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*/
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namespace Zend\EventManager\Test;
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use PHPUnit_Framework_TestCase as TestCase;
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use ReflectionProperty;
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use Zend\EventManager\EventManager;
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use Zend\Stdlib\PriorityQueue;
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/**
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* Trait providing utility methods and assertions for use in PHPUnit test cases.
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*
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* This trait may be composed into a test case, and provides:
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*
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* - methods for introspecting events and listeners
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* - methods for asserting listeners are attached at a specific priority
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*
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* Some functionality in this trait duplicates functionality present in the
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* version 2 EventManagerInterface and/or EventManager implementation, but
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* abstracts that functionality for use in v3. As such, components or code
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* that is testing for listener registration should use the methods in this
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* trait to ensure tests are forwards-compatible between zend-eventmanager
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* versions.
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*/
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trait EventListenerIntrospectionTrait
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{
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/**
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* Retrieve a list of event names from an event manager.
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*
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* @param EventManager $events
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* @return string[]
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*/
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private function getEventsFromEventManager(EventManager $events)
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{
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return $events->getEvents();
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}
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/**
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* Retrieve an interable list of listeners for an event.
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*
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* Given an event and an event manager, returns an iterator with the
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* listeners for that event, in priority order.
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*
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* If $withPriority is true, the key values will be the priority at which
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* the given listener is attached.
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*
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* Do not pass $withPriority if you want to cast the iterator to an array,
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* as many listeners will likely have the same priority, and thus casting
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* will collapse to the last added.
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*
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* @param string $event
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* @param EventManager $events
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* @param bool $withPriority
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* @return \Traversable
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*/
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private function getListenersForEvent($event, EventManager $events, $withPriority = false)
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{
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$listeners = $events->getListeners($event);
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return $this->traverseListeners($listeners, $withPriority);
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}
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/**
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* Assert that a given listener exists at the specified priority.
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*
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* @param callable $expectedListener
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* @param int $expectedPriority
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* @param string $event
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* @param EventManager $events
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* @param string $message Failure message to use, if any.
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*/
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private function assertListenerAtPriority(
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callable $expectedListener,
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$expectedPriority,
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$event,
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EventManager $events,
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$message = ''
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) {
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$message = $message ?: sprintf(
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'Listener not found for event "%s" and priority %d',
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$event,
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$expectedPriority
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);
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$listeners = $this->getListenersForEvent($event, $events, true);
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$found = false;
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foreach ($listeners as $priority => $listener) {
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if ($listener === $expectedListener
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&& $priority === $expectedPriority
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) {
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$found = true;
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break;
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}
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}
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TestCase::assertTrue($found, $message);
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}
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/**
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* Returns an indexed array of listeners for an event.
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*
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* Returns an indexed array of listeners for an event, in priority order.
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* Priority values will not be included; use this only for testing if
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* specific listeners are present, or for a count of listeners.
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*
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* @param string $event
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* @param EventManager $events
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* @return callable[]
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*/
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private function getArrayOfListenersForEvent($event, EventManager $events)
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{
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return iterator_to_array($this->getListenersForEvent($event, $events));
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}
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/**
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* Generator for traversing listeners in priority order.
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*
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* @param PriorityQueue $listeners
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* @param bool $withPriority When true, yields priority as key.
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*/
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public function traverseListeners(PriorityQueue $queue, $withPriority = false)
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{
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foreach ($queue as $handler) {
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$listener = $handler->getCallback();
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if ($withPriority) {
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$priority = (int) $handler->getMetadatum('priority');
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yield $priority => $listener;
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} else {
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yield $listener;
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}
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}
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}
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}

‎test/Test/EventListenerIntrospectionTraitTest.php

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<?php
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/**
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* Zend Framework (http://framework.zend.com/)
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*
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* @link http://github.com/zendframework/zend-eventmanager for the canonical source repository
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* @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
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* @license https://github.com/zendframework/zend-eventmanager/blob/master/LICENSE.md
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*/
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namespace ZendTest\EventManager\Test;
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use PHPUnit_Framework_ExpectationFailedException as ExpectationFailedException;
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use PHPUnit_Framework_TestCase as TestCase;
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use Traversable;
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use Zend\EventManager\EventManager;
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use Zend\EventManager\Test\EventListenerIntrospectionTrait;
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class EventListenerIntrospectionTraitTest extends TestCase
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{
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use EventListenerIntrospectionTrait;
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public function setUp()
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{
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$this->events = new EventManager();
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}
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public function testGetEventsFromEventManagerReturnsEventList()
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{
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// @codingStandardsIgnoreStart
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$this->events->attach('foo', function ($e) {});
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$this->events->attach('bar', function ($e) {});
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$this->events->attach('baz', function ($e) {});
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// @codingStandardsIgnoreEnd
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$this->assertEquals(['foo', 'bar', 'baz'], $this->getEventsFromEventManager($this->events));
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}
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public function testGetListenersForEventReturnsIteratorOfListenersForEventInPriorityOrder()
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{
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// @codingStandardsIgnoreStart
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$callback1 = function ($e) {};
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$callback2 = function ($e) {};
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$callback3 = function ($e) {};
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$callback4 = function ($e) {};
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$callback5 = function ($e) {};
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// @codingStandardsIgnoreEnd
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$this->events->attach('foo', $callback5, 1);
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$this->events->attach('foo', $callback1, 2);
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$this->events->attach('foo', $callback4, 3);
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$this->events->attach('foo', $callback3, 4);
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$this->events->attach('foo', $callback2, 5);
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$listeners = $this->getListenersForEvent('foo', $this->events);
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$this->assertInstanceOf(Traversable::class, $listeners);
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$listeners = iterator_to_array($listeners);
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$this->assertEquals([
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$callback5,
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$callback1,
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$callback4,
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$callback3,
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$callback2,
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], $listeners);
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}
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public function testGetListenersForEventReturnsIteratorOfListenersInAttachmentOrderWhenSamePriority()
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{
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// @codingStandardsIgnoreStart
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$callback1 = function ($e) {};
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$callback2 = function ($e) {};
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$callback3 = function ($e) {};
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$callback4 = function ($e) {};
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$callback5 = function ($e) {};
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// @codingStandardsIgnoreEnd
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$this->events->attach('foo', $callback5);
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$this->events->attach('foo', $callback1);
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$this->events->attach('foo', $callback4);
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$this->events->attach('foo', $callback3);
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$this->events->attach('foo', $callback2);
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$listeners = $this->getListenersForEvent('foo', $this->events);
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$this->assertInstanceOf(Traversable::class, $listeners);
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$listeners = iterator_to_array($listeners);
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$this->assertEquals([
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$callback5,
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$callback1,
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$callback4,
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$callback3,
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$callback2,
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], $listeners);
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}
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public function testGetListenersForEventCanReturnPriorityKeysWhenRequested()
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{
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// @codingStandardsIgnoreStart
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$callback1 = function ($e) {};
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$callback2 = function ($e) {};
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$callback3 = function ($e) {};
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$callback4 = function ($e) {};
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$callback5 = function ($e) {};
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// @codingStandardsIgnoreEnd
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$this->events->attach('foo', $callback5, 1);
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$this->events->attach('foo', $callback1, 2);
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$this->events->attach('foo', $callback4, 3);
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$this->events->attach('foo', $callback3, 4);
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$this->events->attach('foo', $callback2, 5);
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$listeners = $this->getListenersForEvent('foo', $this->events, true);
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$this->assertInstanceOf(Traversable::class, $listeners);
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$listeners = iterator_to_array($listeners);
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$this->assertEquals([
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1 => $callback5,
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2 => $callback1,
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3 => $callback4,
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4 => $callback3,
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5 => $callback2,
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], $listeners);
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}
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public function testGetArrayOfListenersForEventReturnsArrayOfListenersInPriorityOrder()
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{
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// @codingStandardsIgnoreStart
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$callback1 = function ($e) {};
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$callback2 = function ($e) {};
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$callback3 = function ($e) {};
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$callback4 = function ($e) {};
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$callback5 = function ($e) {};
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// @codingStandardsIgnoreEnd
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$this->events->attach('foo', $callback5, 1);
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$this->events->attach('foo', $callback1, 1);
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$this->events->attach('foo', $callback4, 3);
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$this->events->attach('foo', $callback3, 2);
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$this->events->attach('foo', $callback2, 2);
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$listeners = $this->getArrayOfListenersForEvent('foo', $this->events);
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$this->assertInternalType('array', $listeners);
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$this->assertEquals([
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$callback5,
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$callback1,
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$callback3,
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$callback2,
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$callback4,
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], $listeners);
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}
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public function testAssertListenerAtPriorityPassesWhenListenerIsFound()
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{
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// @codingStandardsIgnoreStart
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$callback = function ($e) {};
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// @codingStandardsIgnoreEnd
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$this->events->attach('foo', $callback, 7);
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$this->assertListenerAtPriority($callback, 7, 'foo', $this->events);
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}
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public function testAssertListenerAtPriorityFailsWhenListenerIsNotFound()
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{
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// @codingStandardsIgnoreStart
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$event = 'foo';
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$listener = function ($e) {};
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$priority = 7;
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$this->events->attach($event, $listener, $priority);
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$alternate = function ($e) {};
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$permutations = [
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'different-listener' => ['listener' => $alternate, 'priority' => $priority, 'event' => $event],
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'different-priority' => ['listener' => $listener, 'priority' => $priority + 1, 'event' => $event],
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'different-event' => ['listener' => $listener, 'priority' => $priority, 'event' => $event . '-FOO'],
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];
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// @codingStandardsIgnoreEnd
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foreach ($permutations as $case => $arguments) {
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try {
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$this->assertListenerAtPriority(
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$arguments['listener'],
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$arguments['priority'],
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$arguments['event'],
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$this->events
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);
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$this->fail('assertListenerAtPriority assertion had a false positive for case ' . $case);
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} catch (ExpectationFailedException $e) {
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$this->assertContains(sprintf(
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'Listener not found for event "%s" and priority %d',
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$arguments['event'],
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$arguments['priority']
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), $e->getMessage(), sprintf('Assertion failure message was unexpected: %s', $e->getMessage()));
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}
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}
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}
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}

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