Add tests

Author: sebastianbergmann

tests/unit/Event/FacadeTest.php

@@ -0,0 +1,44 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace PHPUnit\Event;
+
+use PHPUnit\Event\Tracer\Tracer;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\Attributes\Small;
+use PHPUnit\Framework\TestCase;
+
+#[CoversClass(Facade::class)]
+#[Small]
+final class FacadeTest extends TestCase
+{
+    public function testSubscriberRegistrationDoesNotWorkWhenEventFacadeIsSealed(): void
+    {
+        $this->expectException(EventFacadeIsSealedException::class);
+
+        Facade::instance()->registerSubscriber(
+            new class implements Subscriber
+            {},
+        );
+    }
+
+    public function testTracerRegistrationDoesNotWorkWhenEventFacadeIsSealed(): void
+    {
+        $this->expectException(EventFacadeIsSealedException::class);
+
+        Facade::instance()->registerTracer(
+            new class implements Tracer
+            {
+                public function trace(Event $event): void
+                {
+                }
+            },
+        );
+    }
+}