How to check widget is visible when testing

Question

In my case, when I using ExpansionPanelList, I need to check widget inside panel is visible.

If not visible, tester.tap(find.text('More Info')) will throw exception:

Warning: A call to tap() with finder "exactly one widget with text "More Info" (ignoring offstage widgets): Text("More Info", dependencies: [MediaQuery, DefaultTextStyle])" derived an Offset (Offset(400.0, 641.8)) that would not hit test on the specified widget. Maybe the widget is actually off-screen, or another widget is obscuring it, or the widget cannot receive pointer events. Indeed, Offset(400.0, 641.8) is outside the bounds of the root of the render tree, Size(800.0, 600.0). The finder corresponds to this RenderBox: RenderParagraph#1b6b1 relayoutBoundary=up27 The hit test result at that offset is: HitTestResult(HitTestEntry#b18dd(RenderView#408c3), HitTestEntry#a2393()) #0 WidgetController._getElementPoint (package:flutter_test/src/controller.dart:953:25) #1 WidgetController.getCenter (package:flutter_test/src/controller.dart:836:12) #2 WidgetController.tap (package:flutter_test/src/controller.dart:271:18) #3 main. (file:///Users/tommy/Repos/surveyapp/survey/test/widget_test.dart:99:18)

How do I check this widget is visible in testing?

Dan Syrstad · Accepted Answer · 2022-06-23 18:35:06Z

29

Use hitTestable(), which produces a finder which only matches if the widget described by your finder is truly visible on the screen. For example:

  expect(find.text('More Info').hitTestable(), findsOneWidget);

In your case, you may need to wait until the ExpansionPanelList expands or the list scrolls into view. You may need to use pumpSettle() or ensureVisible() first.

answered Jun 23, 2022 at 18:35

Dan Syrstad

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Paul Grei Over a year ago

Perfect answer! :)

呂學洲 · Accepted Answer · 2022-05-26 01:43:07Z

1

RednerObject has a property called _needsPaint and its getter debugNeedsPaint, when this object is visible it should be true.

final targetWidget = find.text('More Info').evaluate().first;
expect(targetWidget.renderObject!.debugNeedsPaint, isTrue);

But when ExpansionPanelList close again, the paint state is still showing it has been paint.

Another work around is that you can ignore the warning and check the side affect.

For example, when tap the hidden widget, it should pop up some view with text Hello World:

await tester.tap(find.text('More Info'), warnIfMissed: false);
expect(find.text('Hello World'), findsOneWidget);

edited May 26, 2022 at 1:43

answered Jul 7, 2021 at 3:54

呂學洲

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