[TASK] Ensure error_reporting uses E_ALL

tests/EnvironmentTest.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the TYPO3 project.
+ *
+ * It is free software; you can redistribute it and/or modify it under the terms
+ * of the MIT License (MIT). For the full copyright and license information,
+ * please read the LICENSE file that was distributed with this source code.
+ *
+ * The TYPO3 project - inspiring people to share!
+ */
+
+namespace TYPO3\HtmlSanitizer\Tests;
+
+use PHPUnit\Framework\TestCase;
+
+class EnvironmentTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function reportsAllErrors(): void
+    {
+        self::assertSame(E_ALL, error_reporting());
+    }
+}