qa: provide tests for ErrorEvent

Adds ErrorEventTest, to test the behavior of ErrorEvent. Discovered a
typo on the constructor as a result, which is now fixed.

Author: weierophinney

src/ErrorEvent.php

@@ -21,7 +21,7 @@ final class ErrorEvent extends \Exception
 
     public function __construct(object $event, callable $listener, Throwable $throwable)
     {
-        parent::__construct($throwable->getMessage, $throwable->getCode(), $throwable);
+        parent::__construct($throwable->getMessage(), $throwable->getCode(), $throwable);
         $this->event    = $event;
         $this->listener = $listener;
     }

test/ErrorEventTest.php

@@ -0,0 +1,38 @@
+<?php
+/**
+ * @see       https://github.com/phly/phly-event-dispatcher for the canonical source repository
+ * @copyright Copyright (c) 2019 Matthew Weier O'Phinney (https:/mwop.net)
+ * @license   https://github.com/phly/phly-event-dispatcher/blob/master/LICENSE.md New BSD License
+ */
+
+declare(strict_types=1);
+
+namespace PhlyTest\EventDispatcher;
+
+use Phly\EventDispatcher\ErrorEvent;
+use PhlyTest\EventDispatcher\TestAsset\TestEvent;
+use PHPUnit\Framework\TestCase;
+use RuntimeException;
+
+class ErrorEventTest extends TestCase
+{
+    public function testErrorEventComposesEventListenerAndThrowable()
+    {
+        $message   = 'ERROR MESSAGE';
+        $code      = 12345;
+        $event     = new TestEvent();
+        $listener  = function (TestEvent $event) {
+        };
+        $exception = new RuntimeException($message, $code);
+
+        $errorEvent = new ErrorEvent($event, $listener, $exception);
+
+        $this->assertSame($event, $errorEvent->getEvent());
+        $this->assertSame($listener, $errorEvent->getListener());
+        $this->assertSame($exception, $errorEvent->getThrowable());
+
+        $this->assertSame($message, $errorEvent->getMessage());
+        $this->assertSame($code, $errorEvent->getCode());
+        $this->assertSame($exception, $errorEvent->getPrevious());
+    }
+}