Add tests for the event dispatcher.

Author: szvsky

packages/Events/tests/EventDispatcherTest.php

@@ -0,0 +1,67 @@
+<?php
+
+/*
+ * This file is part of the aether/aether.
+ *
+ * Copyright (C) 2024 Dominik Szamburski
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license. See the LICENSE file for details.
+ */
+
+namespace Aether\Tests\Events;
+
+use Aether\Events\Event;
+use Aether\Events\EventDispatcher;
+use Aether\Events\EventDispatcherInterface;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+
+#[CoversClass(EventDispatcher::class)]
+class EventDispatcherTest extends TestCase
+{
+    private EventDispatcherInterface $dispatcher;
+
+    protected function setUp(): void
+    {
+        $this->dispatcher = new EventDispatcher();
+    }
+
+    public function testDispatchesWithoutListeners(): void
+    {
+        $listeners = $this->dispatcher->getListeners('event');
+
+        self::assertEmpty($listeners);
+        self::assertCount(0, $listeners);
+    }
+
+    public function testDispatchShouldInvokeListener(): void
+    {
+        $invoked = false;
+
+        $this->dispatcher->listen('test.event', function () use (&$invoked) {
+            $invoked = true;
+        });
+
+        $this->dispatcher->dispatch(new class () {}, 'test.event');
+
+        self::assertTrue($invoked, 'Listener should be invoked on event dispatch.');
+    }
+
+    public function testDispatchShouldNotInvokeListenerAfterPropagationStopped(): void
+    {
+        $invokedAfterStop = false;
+
+        $this->dispatcher->listen('test.event', function (Event $event) {
+            $event->setPropagationStopped();
+        });
+
+        $this->dispatcher->listen('test.event', function () use (&$invokedAfterStop) {
+            $invokedAfterStop = true;
+        });
+
+        $this->dispatcher->dispatch(new Event(), 'test.event');
+
+        self::assertFalse($invokedAfterStop, 'Listener should not be invoked after propagation is stopped');
+    }
+}