Function withConnectedSocket

packages/client/lib/client/socket.spec.ts:108–137

(
      fn: (socket: RedisSocket, underlying: net.Socket) => Promise<void>
    )

    }

    async function withConnectedSocket(
      fn: (socket: RedisSocket, underlying: net.Socket) => Promise<void>
    ) {
      const server = net.createServer();
      server.on('connection', conn => conn.on('error', () => { /* ignore */ }));
      await new Promise<void>(resolve => server.listen(0, '127.0.0.1', resolve));
      const { port } = server.address() as net.AddressInfo;

      const capture = captureUnderlyingSocket();
      try {
        const socket = createSocket({
          host: '127.0.0.1',
          port,
          reconnectStrategy: false
        });

        await socket.connect();
        assert.ok(capture.captured.socket, 'captured underlying socket');

        try {
          await fn(socket, capture.captured.socket!);
        } finally {
          // Tear down the connection so server.close() doesn't wait for it.
          capture.captured.socket?.destroy();
        }
      } finally {
        capture.restore();
        await new Promise<void>(resolve => server.close(() => resolve()));
      }
    }

    it('should short-circuit when the underlying socket is no longer writable (#3282)', async () => {
      await withConnectedSocket(async (socket, underlying) => {