added unit tests

tests/Support/RawHttpResponse.php

@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Support;
+
+use RuntimeException;
+
+/** Thrown instead of exit() for file/download responses when QDB_TESTING is defined. */
+final class RawHttpResponse extends RuntimeException
+{
+    /**
+     * @param array<string, string> $headers
+     */
+    public function __construct(
+        public readonly string $body,
+        public readonly array $headers,
+        public readonly int $httpStatus = 200,
+    ) {
+        parent::__construct('Raw HTTP response', $httpStatus);
+    }
+}