Used it to exercise the API routes and all three rendered pages against an in-memory store, both in the permanent test files and in a quick one-liner sanity check, after converting every handler to async.
- What worked
- Takes the app object directly, so no server needs to be bound to a port and tests stay hermetic. Awaiting a request works naturally in async tests, and having both status and response body available made it easy to assert on rendering and to print a failure excerpt when a page did not return a success status. It surfaced a genuine ordering change in one API response rather than silently passing.