Add a test demonstrating that there is no warning when double rendering on the client a server component that used useId

Author: gnoff

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -563,6 +563,47 @@ describe('ReactFlight', () => {
         </>,
       );
     });
+
+    // @gate enableServerContext
+    it('[TODO] it does not warn if you render a server element passed to a client module reference twice on the client when using useId', async () => {
+      // @TODO Today if you render a server component with useId and pass it to a client component and that client component renders the element in two or more
+      // places the id used on the server will be duplicated in the client. This is a deviation from the guarantees useId makes for Fizz/Client and is a consequence
+      // of the fact that the server component is actually rendered on the server and is reduced to a set of host elements before being passed to the Client component
+      // so the output passed to the Client has no knowledge of the useId use. In the future we would like to add a DEV warning when this happens. For now
+      // we just accept that it is a nuance of useId in Flight
+      function App() {
+        let id = React.useId();
+        let div = <div prop={id}>{id}</div>;
+        return <ClientDoublerModuleRef el={div} />;
+      }
+
+      function ClientDoubler({el}) {
+        Scheduler.unstable_yieldValue('ClientDoubler');
+        return (
+          <>
+            {el}
+            {el}
+          </>
+        );
+      }
+
+      const ClientDoublerModuleRef = moduleReference(ClientDoubler);
+
+      const transport = ReactNoopFlightServer.render(<App />);
+      expect(Scheduler).toHaveYielded([]);
+
+      act(() => {
+        ReactNoop.render(ReactNoopFlightClient.read(transport));
+      });
+
+      expect(Scheduler).toHaveYielded(['ClientDoubler']);
+      expect(ReactNoop).toMatchRenderedOutput(
+        <>
+          <div prop=":S1:">:S1:</div>
+          <div prop=":S1:">:S1:</div>
+        </>,
+      );
+    });
   });
 
   describe('ServerContext', () => {