--- /dev/null
+<?php
+
+namespace Drupal\KernelTests\Core\File;
+
+use Drupal\KernelTests\KernelTestBase;
+use Symfony\Component\HttpFoundation\Request;
+
+/**
+ * Tests url transform to relative.
+ *
+ * @group Utility
+ */
+class UrlTransformRelativeTest extends KernelTestBase {
+
+ public static $modules = ['file_test'];
+
+ /**
+ * Tests file_url_transform_relative function.
+ *
+ * @dataProvider providerFileUrlTransformRelative
+ */
+ public function testFileUrlTransformRelative($host, $port, $https, $url, $expected) {
+
+ $_SERVER['REMOTE_ADDR'] = '127.0.0.1';
+ $_SERVER['SERVER_ADDR'] = '127.0.0.1';
+ $_SERVER['SERVER_PORT'] = $port;
+ $_SERVER['SERVER_SOFTWARE'] = NULL;
+ $_SERVER['SERVER_NAME'] = $host;
+ $_SERVER['REQUEST_URI'] = '/';
+ $_SERVER['REQUEST_METHOD'] = 'GET';
+ $_SERVER['SCRIPT_NAME'] = '/index.php';
+ $_SERVER['SCRIPT_FILENAME'] = '/index.php';
+ $_SERVER['PHP_SELF'] = '/index.php';
+ $_SERVER['HTTP_USER_AGENT'] = 'Drupal command line';
+ $_SERVER['HTTPS'] = $https;
+
+ $request = Request::createFromGlobals();
+ \Drupal::requestStack()->push($request);
+
+ $this->assertSame($expected, file_url_transform_relative($url));
+ }
+
+ public function providerFileUrlTransformRelative() {
+ $data = [];
+ $data[] = [
+ 'example.com',
+ 80,
+ '',
+ 'http://example.com/page',
+ '/page',
+ ];
+ $data[] = [
+ 'example.com',
+ 443,
+ 'on',
+ 'https://example.com/page',
+ '/page',
+ ];
+ $data[] = [
+ 'example.com',
+ 8080,
+ '',
+ 'https://example.com:8080/page',
+ '/page',
+ ];
+ $data[] = [
+ 'example.com',
+ 8443,
+ 'on',
+ 'https://example.com:8443/page',
+ '/page',
+ ];
+ $data[] = [
+ 'example.com',
+ 80,
+ '',
+ 'http://exampleXcom/page',
+ 'http://exampleXcom/page',
+ ];
+ return $data;
+ }
+
+}