flutter/packages/flutter/test/material/switch_test.dart

// Copyright 2016 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/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter_test/flutter_test.dart';

void main() {
  testWidgets('Switch can toggle on tap', (WidgetTester tester) async {
    final Key switchKey = new UniqueKey();
    bool value = false;

    await tester.pumpWidget(
      new StatefulBuilder(
        builder: (BuildContext context, StateSetter setState) {
          return new Material(
            child: new Center(
              child: new Switch(
                key: switchKey,
                value: value,
                onChanged: (bool newValue) {
                  setState(() {
                    value = newValue;
                  });
                }
              )
            )
          );
        }
      )
    );

    expect(value, isFalse);
    await tester.tap(find.byKey(switchKey));
    expect(value, isTrue);
  });

  testWidgets('Switch can drag', (WidgetTester tester) async {
    bool value = false;

    await tester.pumpWidget(
      new StatefulBuilder(
        builder: (BuildContext context, StateSetter setState) {
          return new Material(
            child: new Center(
              child: new Switch(
                value: value,
                onChanged: (bool newValue) {
                  setState(() {
                    value = newValue;
                  });
                }
              )
            )
          );
        }
      )
    );

    expect(value, isFalse);

    await tester.drag(find.byType(Switch), const Offset(-30.0, 0.0));

    expect(value, isFalse);

    await tester.drag(find.byType(Switch), const Offset(30.0, 0.0));

    expect(value, isTrue);

    await tester.pump();
    await tester.drag(find.byType(Switch), const Offset(30.0, 0.0));

    expect(value, isTrue);

    await tester.pump();
    await tester.drag(find.byType(Switch), const Offset(-30.0, 0.0));

    expect(value, isFalse);
  });
}