[webview_flutter] Use a local web server for legacy web integration tests

packages/webview_flutter/webview_flutter_web/example/integration_test/legacy/webview_flutter_test.dart

@@ -4,22 +4,35 @@
 
 import 'dart:async';
 import 'dart:html' as html;
+import 'dart:io';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:integration_test/integration_test.dart';
 import 'package:webview_flutter_web_example/legacy/web_view.dart';
 
-void main() {
+void main() async {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();
 
-  // URLs to navigate to in tests. These need to be URLs that we are confident will
-  // always be accessible, and won't do redirection. (E.g., just
-  // 'https://www.google.com/' will sometimes redirect traffic that looks
-  // like it's coming from a bot, which is true of these tests).
-  const String primaryUrl = 'https://flutter.dev/';
-  const String secondaryUrl = 'https://www.google.com/robots.txt';
+  const String primaryPage = 'first.txt';
+  const String secondaryPage = 'second.txt';
+  final HttpServer server =
+      await HttpServer.bind(InternetAddress.loopbackIPv4, 0);
+  unawaited(server.forEach((HttpRequest request) {
+    if (request.uri.path == '/$primaryPage') {
+      request.response.writeln('Hello, world.');
+    }
+    if (request.uri.path == '/$secondaryPage') {
+      request.response.writeln('Another page.');
+    } else {
+      fail('unexpected request: ${request.method} ${request.uri}');
+    }
+    request.response.close();
+  }));
+  final String prefixUrl = 'http://localhost:${server.port}';
+  final String primaryUrl = '$prefixUrl/$primaryPage';
+  final String secondaryUrl = '$prefixUrl/$secondaryPage';
 
   testWidgets('initialUrl', (WidgetTester tester) async {
     final Completer<WebViewController> controllerCompleter =

script/tool/lib/src/drive_examples_command.dart

@@ -317,7 +317,8 @@ class DriveExamplesCommand extends PackageLoopingCommand {
         example.directory.childDirectory('integration_test');
 
     if (integrationTestDir.existsSync()) {
-      await for (final FileSystemEntity file in integrationTestDir.list()) {
+      await for (final FileSystemEntity file
+          in integrationTestDir.list(recursive: true)) {
         if (file is File && file.basename.endsWith('_test.dart')) {
           tests.add(file);
         }