added unit tests

tests/Support/TestFilesystem.php

@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Support;
+
+final class TestFilesystem
+{
+    public static function resetUploads(): void
+    {
+        if (!defined('QDB_TEST_UPLOADS')) {
+            return;
+        }
+        if (defined('QDB_PATH')) {
+            if (is_file(QDB_PATH)) {
+                @unlink(QDB_PATH);
+            }
+            if (defined('QDB_LOCK') && is_file(QDB_LOCK)) {
+                @unlink(QDB_LOCK);
+            }
+        }
+        self::rmTree(QDB_TEST_UPLOADS);
+        mkdir(QDB_TEST_UPLOADS, 0755, true);
+    }
+
+    private static function rmTree(string $dir): void
+    {
+        if (!is_dir($dir)) {
+            return;
+        }
+        $items = scandir($dir);
+        if ($items === false) {
+            return;
+        }
+        foreach ($items as $item) {
+            if ($item === '.' || $item === '..') {
+                continue;
+            }
+            $path = $dir . DIRECTORY_SEPARATOR . $item;
+            if (is_dir($path)) {
+                self::rmTree($path);
+            } else {
+                @unlink($path);
+            }
+        }
+        @rmdir($dir);
+    }
+}