add serializer test

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>

tests/lib/Log/ExceptionSerializerTest.php

@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2021 Arthur Schiwon <blizzz@arthur-schiwon.de>
+ *
+ * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace lib\Log;
+
+use OC\Log\ExceptionSerializer;
+use OC\SystemConfig;
+use Test\TestCase;
+
+class ExceptionSerializerTest extends TestCase {
+	private $serializer;
+
+	public function setUp(): void {
+		parent::setUp();
+
+		$config = $this->createMock(SystemConfig::class);
+		$this->serializer = new ExceptionSerializer($config);
+	}
+
+	private function emit($arguments) {
+		\call_user_func_array([$this, 'bind'], $arguments);
+	}
+
+	private function bind(array &$myValues): void {
+		throw new \Exception('my exception');
+	}
+
+	/**
+	 * this test ensures that the serializer does not overwrite referenced
+	 * variables. It is crafted after a scenario we experienced: the DAV server
+	 * emitting the "validateTokens" event, of which later on a handled
+	 * exception was passed to the logger. The token was replaced, the original
+	 * variable overwritten.
+	 */
+	public function testSerializer() {
+		try {
+			$secret = ['Secret'];
+			$this->emit([&$secret]);
+		} catch (\Exception $e) {
+			$this->serializer->serializeException($e);
+			$this->assertSame(['Secret'], $secret);
+		}
+	}
+}