Add:创建 flutter go web 版

packages/flutter_web/test/widgets/syncing_test.dart

@@ -0,0 +1,151 @@
+// 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_test/flutter_web_test.dart';
+import 'package:flutter_web/widgets.dart';
+
+class TestWidget extends StatefulWidget {
+  const TestWidget({this.child, this.persistentState, this.syncedState});
+
+  final Widget child;
+  final int persistentState;
+  final int syncedState;
+
+  @override
+  TestWidgetState createState() => TestWidgetState();
+}
+
+class TestWidgetState extends State<TestWidget> {
+  int persistentState;
+  int syncedState;
+  int updates = 0;
+
+  @override
+  void initState() {
+    super.initState();
+    persistentState = widget.persistentState;
+    syncedState = widget.syncedState;
+  }
+
+  @override
+  void didUpdateWidget(TestWidget oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    syncedState = widget.syncedState;
+    // we explicitly do NOT sync the persistentState from the new instance
+    // because we're using that to track whether we got recreated
+    updates += 1;
+  }
+
+  @override
+  Widget build(BuildContext context) => widget.child;
+}
+
+void main() {
+  testWidgets('no change', (WidgetTester tester) async {
+    await tester.pumpWidget(Container(
+        child: Container(
+            child: TestWidget(persistentState: 1, child: Container()))));
+
+    final TestWidgetState state = tester.state(find.byType(TestWidget));
+
+    expect(state.persistentState, equals(1));
+    expect(state.updates, equals(0));
+
+    await tester.pumpWidget(Container(
+        child: Container(
+            child: TestWidget(persistentState: 2, child: Container()))));
+
+    expect(state.persistentState, equals(1));
+    expect(state.updates, equals(1));
+
+    await tester.pumpWidget(Container());
+  });
+
+  testWidgets('remove one', (WidgetTester tester) async {
+    await tester.pumpWidget(Container(
+        child: Container(
+            child: TestWidget(persistentState: 10, child: Container()))));
+
+    TestWidgetState state = tester.state(find.byType(TestWidget));
+
+    expect(state.persistentState, equals(10));
+    expect(state.updates, equals(0));
+
+    await tester.pumpWidget(
+        Container(child: TestWidget(persistentState: 11, child: Container())));
+
+    state = tester.state(find.byType(TestWidget));
+
+    expect(state.persistentState, equals(11));
+    expect(state.updates, equals(0));
+
+    await tester.pumpWidget(Container());
+  });
+
+  testWidgets('swap instances around', (WidgetTester tester) async {
+    const Widget a = TestWidget(
+        persistentState: 0x61,
+        syncedState: 0x41,
+        child: Text('apple', textDirection: TextDirection.ltr));
+    const Widget b = TestWidget(
+        persistentState: 0x62,
+        syncedState: 0x42,
+        child: Text('banana', textDirection: TextDirection.ltr));
+    await tester.pumpWidget(Column());
+
+    final GlobalKey keyA = GlobalKey();
+    final GlobalKey keyB = GlobalKey();
+
+    await tester.pumpWidget(Column(children: <Widget>[
+      Container(key: keyA, child: a),
+      Container(key: keyB, child: b)
+    ]));
+
+    TestWidgetState first, second;
+
+    first = tester.state(find.byWidget(a));
+    second = tester.state(find.byWidget(b));
+
+    expect(first.widget, equals(a));
+    expect(first.persistentState, equals(0x61));
+    expect(first.syncedState, equals(0x41));
+    expect(second.widget, equals(b));
+    expect(second.persistentState, equals(0x62));
+    expect(second.syncedState, equals(0x42));
+
+    await tester.pumpWidget(Column(children: <Widget>[
+      Container(key: keyA, child: a),
+      Container(key: keyB, child: b)
+    ]));
+
+    first = tester.state(find.byWidget(a));
+    second = tester.state(find.byWidget(b));
+
+    // same as before
+    expect(first.widget, equals(a));
+    expect(first.persistentState, equals(0x61));
+    expect(first.syncedState, equals(0x41));
+    expect(second.widget, equals(b));
+    expect(second.persistentState, equals(0x62));
+    expect(second.syncedState, equals(0x42));
+
+    // now we swap the nodes over
+    // since they are both "old" nodes, they shouldn't sync with each other even though they look alike
+
+    await tester.pumpWidget(Column(children: <Widget>[
+      Container(key: keyA, child: b),
+      Container(key: keyB, child: a)
+    ]));
+
+    first = tester.state(find.byWidget(b));
+    second = tester.state(find.byWidget(a));
+
+    expect(first.widget, equals(b));
+    expect(first.persistentState, equals(0x61));
+    expect(first.syncedState, equals(0x42));
+    expect(second.widget, equals(a));
+    expect(second.persistentState, equals(0x62));
+    expect(second.syncedState, equals(0x41));
+  });
+}