TestWindow class

Deprecated. Will be removed in a future version of Flutter.

This class has been deprecated to prepare for Flutter's upcoming support for multiple views and multiple windows.

SingletonFlutterWindow that wraps another SingletonFlutterWindow and allows faking of some properties for testing purposes.

Tests for certain widgets, e.g., MaterialApp, might require faking certain properties of a SingletonFlutterWindow. TestWindow facilitates the faking of these properties by overriding the properties of a real SingletonFlutterWindow with desired fake values. The binding used within tests, TestWidgetsFlutterBinding, contains a TestWindow that is used by all tests.

Sample Code

A test can utilize a TestWindow in the following way:

testWidgets('your test name here', (WidgetTester tester) async {
  // Retrieve the TestWidgetsFlutterBinding.
  final TestWidgetsFlutterBinding testBinding = tester.binding;

  // Fake the desired properties of the TestWindow. All code running
  // within this test will perceive the following fake text scale
  // factor as the real text scale factor of the window.
  testBinding.platformDispatcher.textScaleFactorTestValue = 2.5;

  // Test code that depends on text scale factor here.
});

The TestWidgetsFlutterBinding is recreated for each test and therefore any fake values defined in one test will not persist to the next.

If a test needs to override a real SingletonFlutterWindow property and then later return to using the real SingletonFlutterWindow property, TestWindow provides methods to clear each individual test value, e.g., clearDevicePixelRatioTestValue.

To clear all fake test values in a TestWindow, consider using clearAllTestValues.

See also:

• TestPlatformDispatcher, which wraps a PlatformDispatcher for testing purposes and is used by the platformDispatcher property of this class.