Add stress tests for cupertino_http and cronet_http

pkgs/cronet_http/example/integration_test/stress.dart

@@ -0,0 +1,14 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:cronet_http/cronet_http.dart';
+import 'package:http_client_conformance_tests/http_client_conformance_tests.dart';
+import 'package:integration_test/integration_test.dart';
+
+/// Stress tests not run as part of `flutter test integration_test`.
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  stressTestConcurrentRequests(CronetClient.defaultCronetEngine());
+}

pkgs/cupertino_http/example/integration_test/main.dart

@@ -24,6 +24,8 @@ import 'web_socket_conformance_test.dart' as web_socket_conformance_test;
 /// This is faster than running each test individually using
 /// `flutter test integration_test/` because only one compilation step and
 /// application launch is required.
+///
+/// Does **not** run the stress tests.
 void main() {
   IntegrationTestWidgetsFlutterBinding.ensureInitialized();
 

pkgs/cupertino_http/example/integration_test/stress.dart

@@ -0,0 +1,15 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:cupertino_http/cupertino_http.dart';
+import 'package:http_client_conformance_tests/http_client_conformance_tests.dart';
+import 'package:integration_test/integration_test.dart';
+
+/// Stress tests not run as part of `main.dart` or
+/// `flutter test integration_test`.
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  stressTestConcurrentRequests(CupertinoClient.defaultSessionConfiguration());
+}

pkgs/http_client_conformance_tests/lib/http_client_conformance_tests.dart

@@ -4,23 +4,7 @@
 
 import 'package:http/http.dart';
 
-import 'src/close_tests.dart';
-import 'src/compressed_response_body_tests.dart';
-import 'src/isolate_test.dart';
-import 'src/multipart_tests.dart';
-import 'src/multiple_clients_tests.dart';
-import 'src/redirect_tests.dart';
-import 'src/request_body_streamed_tests.dart';
-import 'src/request_body_tests.dart';
-import 'src/request_cookies_test.dart';
-import 'src/request_headers_tests.dart';
-import 'src/request_methods_tests.dart';
-import 'src/response_body_streamed_test.dart';
-import 'src/response_body_tests.dart';
-import 'src/response_cookies_test.dart';
-import 'src/response_headers_tests.dart';
-import 'src/response_status_line_tests.dart';
-import 'src/server_errors_test.dart';
+import 'http_client_conformance_tests.dart';
 
 export 'src/close_tests.dart' show testClose;
 export 'src/compressed_response_body_tests.dart'
@@ -40,6 +24,7 @@ export 'src/response_cookies_test.dart' show testResponseCookies;
 export 'src/response_headers_tests.dart' show testResponseHeaders;
 export 'src/response_status_line_tests.dart' show testResponseStatusLine;
 export 'src/server_errors_test.dart' show testServerErrors;
+export 'src/stress_test.dart' show stressTestConcurrentRequests;
 
 /// Runs the entire test suite against the given [Client].
 ///

pkgs/http_client_conformance_tests/lib/src/stress_test.dart

@@ -0,0 +1,65 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:async/async.dart';
+import 'package:http/http.dart';
+import 'package:stream_channel/stream_channel.dart';
+import 'package:test/test.dart';
+
+import 'response_body_server_vm.dart'
+    if (dart.library.js_interop) 'response_body_server_web.dart';
+
+/// Test that the [Client] can perform many concurrent HTTP requests without
+/// error.
+///
+/// `concurrentRequests` controls the number of requests that will be made
+/// simultaneously. If set too large, this may overload the HTTP server.
+///
+/// NOTE: These tests are not run by `testAll`.
+void stressTestConcurrentRequests(Client client,
+    {int numRequests = 100000, int concurrentRequests = 10}) async {
+  group('stress concurrent requests', () {
+    late final String host;
+    late final StreamChannel<Object?> httpServerChannel;
+    late final StreamQueue<Object?> httpServerQueue;
+
+    setUpAll(() async {
+      httpServerChannel = await startServer();
+      httpServerQueue = StreamQueue(httpServerChannel.stream);
+      host = 'localhost:${await httpServerQueue.nextAsInt}';
+    });
+    tearDownAll(() => httpServerChannel.sink.add(null));
+
+    test('small response', () async {
+      var requestCount = 0;
+      var completeCount = 0;
+      final c = Completer<void>();
+
+      void request() {
+        client.get(Uri.http(host, '/$requestCount')).then((response) {
+          expect(response.statusCode, 200);
+          ++completeCount;
+          if (requestCount < numRequests) {
+            ++requestCount;
+            request();
+          }
+          if (completeCount == numRequests) {
+            c.complete();
+          }
+        },
+            onError: (Object e, _) =>
+                c.completeError(e, StackTrace.empty)).ignore();
+      }
+
+      for (requestCount = 0;
+          requestCount < concurrentRequests;
+          ++requestCount) {
+        request();
+      }
+      await c.future;
+    });
+  });
+}