When any component or page that is a client or server component uses another server-component within itself, any test-case that tests this component will fail due to this error:
Error: Objects are not valid as a React child (found: [object Promise]). If you meant to render a collection of children, use an array instead.
Wrapping the server component within a Suspense tag does not resolve this issue either, e.g.:
function AnyComponent() {
return (<div>
...
<Suspense fallback={<div> Loading... </div>}>
<AnyServerComponent/>
</Suspense>
</div>)
}