Add:创建 flutter go web 版

packages/flutter_web/test/widgets/semantics_5_test.dart

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+// Copyright 2015 The Chromium Authors. 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:flutter_web/material.dart';
+import 'package:flutter_web/widgets.dart';
+import 'package:flutter_web_test/flutter_web_test.dart';
+
+import 'semantics_tester.dart';
+
+void main() {
+  testWidgets('Semantics 5', (WidgetTester tester) async {
+    final SemanticsTester semantics = SemanticsTester(tester);
+
+    await tester.pumpWidget(Stack(
+        textDirection: TextDirection.ltr,
+        fit: StackFit.expand,
+        children: <Widget>[
+          Semantics(
+              // this tests that empty nodes disappear
+              ),
+          Semantics(
+            // this tests whether you can have a container with no other semantics
+            container: true,
+          ),
+          Semantics(
+            label: 'label', // (force a fork)
+            textDirection: TextDirection.ltr,
+          ),
+        ]));
+
+    expect(
+        semantics,
+        hasSemantics(TestSemantics.root(children: <TestSemantics>[
+          TestSemantics.rootChild(
+            id: 1,
+            rect: TestSemantics.fullScreen,
+          ),
+          TestSemantics.rootChild(
+            id: 2,
+            label: 'label',
+            rect: TestSemantics.fullScreen,
+          ),
+        ])));
+
+    semantics.dispose();
+  });
+}