Function setup

test/server/proxy-option.test.js:854–885

(devServerOptions)

    // Start a backend WebSocket server (the user proxy target) and a dev-server
    // proxying everything to it, with the given dev-server options merged in.
    const setup = async (devServerOptions) => {
      backendUpgradeCount = 0;

      backend = http.createServer();
      backendWss = new WebSocketServer({ server: backend });
      backendWss.on("connection", () => {
        backendUpgradeCount += 1;
      });

      await new Promise((resolve) => {
        backend.listen(port5, resolve);
      });

      server = new Server(
        {
          hot: true,
          allowedHosts: "all",
          proxy: [
            {
              context: "/",
              target: `http://localhost:${port5}`,
              ws: true,
            },
          ],
          port: port3,
          ...devServerOptions,
        },
        webpack(config),
      );

      await server.start();
    };

    const teardown = async () => {
      for (const client of backendWss.clients) {