pageBack method

Future<void> pageBack ()

Makes an effort to dismiss the current page with a Material Scaffold or a CupertinoPageScaffold.

Will throw an error if there is no back button in the page.

Implementation 

Future<void> pageBack() async {
  return TestAsyncUtils.guard<void>(() async {
    Finder backButton = find.byTooltip('Back');
    if (backButton.evaluate().isEmpty) {
      backButton = find.byType(CupertinoNavigationBarBackButton);
    }

    expectSync(backButton, findsOneWidget, reason: 'One back button expected on screen');

    await tap(backButton);
  });
}