How should I test for Navigator.pushNamed() in Flutter?

Question

I have a test where I'm trying to observe the behaviour of the Navigator when the app navigates from page1.dart to page2.dart (push) and back (pop). Using verify from the Mockito package, I can successfully verify that the push behaviour works when I am not using pushNamed(). However, after I changed my project to use Named Route, I wasn't able to find a correct way to implement the mock and test the navigation.

Is there a proper way how to check, that Navigator was called? Or is there a recommended way to mock and replace the navigator?

Edit: I found a flutter library Mockingjay to Mock the Navigator.

Answer 1

I've found a flutter library Mockingjay to Mock the Navigator.

Here is an example on their GitHub page on testing Navigator.

void main() {
  testWidgets('pushes SettingsPage when TextButton is tapped', (tester) async {
    final navigator = MockNavigator();
    when(() => navigator.push(any())).thenAnswer((_) async {});

    await tester.pumpWidget(
      MaterialApp(
        home: MockNavigatorProvider(
          navigator: navigator,
          child: const MyHomePage(),
        ),
      ),
    );

    await tester.tap(find.byType(TextButton));

    verify(
      () => navigator.push(any(that: isRoute<void>(whereName: equals('/settings')))),
    ).called(1);
  });
}