make sure to generate valid filenames (#2238)

tests/Utils/FileHelperTest.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Utils;
+
+use App\Utils\FileHelper;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \App\Utils\FileHelper
+ */
+class FileHelperTest extends TestCase
+{
+    public function getFileTestData()
+    {
+        return [
+            ['Barss_laolala_ld_ksjf_123_MyAwesome_GmbH', 'Barß / laölala #   ld_ksjf 123 MyAwesome GmbH'],
+            ['namaste', 'नमस्ते'],
+            ['sa_yonara', 'さ!よなら'],
+            ['sp_asibo_spa_sibo_spas_--_ibo', ' сп.асибо/спа   сибо#/!спас -- ибо!!'],
+            ['kkakkaekkyakkyaekkeokke_kkyeokkyekkokkwasssss', '까깨꺄꺠꺼께_껴꼐꼬꽈sssss'],
+            ['ss_n_-', '\"#+ß.!$%&/()=?\\n=/*-+´_<>@' . "\n"],
+            ['Demo_ProjecT1', 'Demo ProjecT1'],
+            ['kimai-export', 'kimai-export'],
+            ['D_e_m_o_Pr_oj_e_c_T1', 'D"e&m%o# Pr\'oj\\e/c?T1'],
+        ];
+    }
+
+    /**
+     * @dataProvider getFileTestData
+     */
+    public function testEnsureMaxLength(string $expected, string $original)
+    {
+        self::assertEquals($expected, FileHelper::convertToAsciiFilename($original));
+    }
+}