Add:创建 flutter go web 版

packages/flutter_web/test/widgets/overflow_box_test.dart

@@ -0,0 +1,47 @@
+// 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/rendering.dart';
+import 'package:flutter_web/widgets.dart';
+
+import 'package:flutter_web_test/flutter_web_test.dart';
+
+void main() {
+  testWidgets('OverflowBox control test', (WidgetTester tester) async {
+    final GlobalKey inner = GlobalKey();
+    await tester.pumpWidget(Align(
+        alignment: const Alignment(1.0, 1.0),
+        child: SizedBox(
+            width: 10.0,
+            height: 20.0,
+            child: OverflowBox(
+                minWidth: 0.0,
+                maxWidth: 100.0,
+                minHeight: 0.0,
+                maxHeight: 50.0,
+                child: Container(key: inner)))));
+    final RenderBox box = inner.currentContext.findRenderObject();
+    expect(box.localToGlobal(Offset.zero), equals(const Offset(745.0, 565.0)));
+    expect(box.size, equals(const Size(100.0, 50.0)));
+  });
+
+  testWidgets('OverflowBox implements debugFillProperties',
+      (WidgetTester tester) async {
+    final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
+    const OverflowBox(
+            minWidth: 1.0, maxWidth: 2.0, minHeight: 3.0, maxHeight: 4.0)
+        .debugFillProperties(builder);
+    final List<String> description = builder.properties
+        .where((DiagnosticsNode n) => !n.isFiltered(DiagnosticLevel.info))
+        .map((DiagnosticsNode n) => n.toString())
+        .toList();
+    expect(description, <String>[
+      'alignment: center',
+      'minWidth: 1.0',
+      'maxWidth: 2.0',
+      'minHeight: 3.0',
+      'maxHeight: 4.0',
+    ]);
+  });
+}