Testing setLocation() redirects with Karibu - How to verify browser navigation?

Flow
1

I’m trying to test a LoginView that redirects authenticated users to a URL specified in a query parameter. The production code works, but I can’t figure out how to test it with Karibu. It’s a medium complexity server-client auth flow that I want to verify.

The code being tested:

@Override
public void beforeEnter(BeforeEnterEvent event) {
    if (authenticatedUser.get().isPresent()) {
        Map<String, List<String>> params = event.getLocation().getQueryParameters().getParameters();
        if (params.containsKey("redirect")) {
            String redirectTarget = params.get("redirect").getFirst();
            if (redirectTarget != null && !redirectTarget.isBlank()) {
                setOpened(false);
                event.getUI().getPage().setLocation(redirectTarget);  // <- This is what I need to test
                return;
            }
        }
        setOpened(false);
        event.forwardTo("");
    }
}

My test:

@Test
    void givenRedirectQueryParam_afterLogin_thenRedirect() {
        accountRepository.deleteAll();
        Account account = new AccountBuilder().build();
        accountRepository.save(account);

        // Step 1: Navigate to login with redirect param (unauthenticated)
        Map<String, List<String>> queryParams = Map.of("redirect", List.of("/api/agent/callback"));
        QueryParameters queryParameters = new QueryParameters(queryParams);
        getCurrent().navigate(LoginView.class, queryParameters);

        // Step 2: Authenticate the user (simulating successful login)
        // Navigate to login AGAIN with the same redirect param
        loginAndNavigate(LoginView.class, queryParameters);
        LoginOverlay loginOverlay = LocatorJ._get(LoginOverlay.class);
        assertThat(loginOverlay.isOpened()).isFalse();
        verifyCurrentViewPath("/api/agent/callback");
    }

The issue appears to be that setLocation() performs a browser-level redirect that Karibu can’t simulate. I can see in the debugger that setLocation() is called with the correct URL, but Karibu doesn’t actually navigate there.

Is there a recommended way to test this behavior? Should I:

  1. Refactor to use forwardTo() instead (but my redirect target is a Spring controller endpoint, not a Vaadin route)
  2. Use a different testing approach for this scenario
  3. Accept this as a Karibu limitation and rely on E2E tests

Any guidance would be appreciated! Using Vaadin 24 with Karibu Testing.

2

In my opinion this is not a test case for Karibu because you want to verify browser behavior. For these kind of tests I use Playwright

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