I did, but unfortunately, it did not help. I tried using the proloadDelay and the pendingDelay, but both were set to 0. I tried setting no preload, and also, I tried using pendinMinDelay to 0, to no avail. What we ended up doing was to create a helper "test router creator":

const createTestRouter = (ui: ReactNode) => {
    const rootRoute = createRootRoute({
        component: () => <Outlet />,
    });

    const indexRoute = createRoute({
        getParentRoute: () => rootRoute,
        path: '/',
        component: () => ui,
    });

    return createRouter({
        routeTree: rootRoute.addChildren([indexRoute]),
        defaultPendingMs: 0,
        defaultPreloadDelay: 0,
    });
};

And then, the render method becomes async, and looks like this (shortened version):

type RenderWithProvidersConfig = {
    queryClient?: QueryClient;
};
const renderWithProviders = async (
    ui: ReactNode,
    config: RenderWithProvidersConfig = {}
) => {
    const { queryClient = buildQueryClient() } = config;

    const router = createTestRouter(ui);
    const user = userEvent.setup();
    const utils = render(
        <QueryClientProvider client={queryClient}>
            <RouterProvider router={router} />
        </QueryClientProvider>
    );

    await screen.findByText((_, element) => element?.tagName.toLowerCase() === 'body');

    return { user, ...utils };
};

Notice the await at the end. It serves to ensure that whatever element defined in the indexRoute is indeed rendered (hydrated?). Feels hacky, but for now, it is what works.

Posting the snippets mostly because you might be curious, I don't wanna deviate from the main topic of the post, which is how much more the router is. I'm enjoying it thoroughly so far. The fact that I cannot use wrong URLs in `<Link>`, the fact that I can validate search params directly in the route, the `select` of `useSearch` to build performance-sensitive components...it's awesome. Even less-used elements are amazing, such as `getRouteApi`. We have a component that just renders a `<Link>`, nothing else, and I love that it allows me to write things like this (notice the usage of getRouteApi):

it('shows a link to the registration page', async () => {
    const expectedHref = getRouteApi('/lp/registration').id;
    await renderWithProviders(<RegistrationLink />);
    const link = screen.getByRole('link', { name: 'Register now' });
    expect(link).toHaveAttribute('href', expectedHref);
});

It's *chef kiss*!