就我而言，当我使用 时ExpansionPanelList，我需要检查面板内的小部件是否可见。
如果不可见，tester.tap(find.text('More Info'))将抛出异常：
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 …