Router Act

If you're writing tests for Next.js client router behavior, this is how you properly test prefetch requests and navigation without flaky polling or retry loops. The createRouterAct utility gives you an end-to-end way to assert on network responses and cache behavior without coupling to protocol details. The core idea is to use LinkAccordion to control prefetch timing and prefer 'no-requests' assertions when data should come from cache, which is the strongest proof your cache actually works. Skip it entirely if you just need to wait for UI to appear after navigation. The skill documentation is opinionated about avoiding the block feature and eliminating inherently flaky patterns, which suggests this comes from real pain points in the Next.js codebase.