Regression test for empty fragments

This was also throwing before we added support for rendering undefined.

Author: eps1lon

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

@@ -213,6 +213,22 @@ describe('ReactFlight', () => {
     expect(ReactNoop).toMatchRenderedOutput(null);
   });
 
+  it('can render an empty fragment', async () => {
+    function Empty() {
+      return <React.Fragment></React.Fragment>;
+    }
+
+    const model = <Empty />;
+
+    const transport = ReactNoopFlightServer.render(model);
+
+    await act(async () => {
+      ReactNoop.render(await ReactNoopFlightClient.read(transport));
+    });
+
+    expect(ReactNoop).toMatchRenderedOutput(null);
+  });
+
   it('can render a lazy component as a shared component on the server', async () => {
     function SharedComponent({text}) {
       return (