hapi-listener-assertions.js

const assert = require("assert");
const hapi = require("hapi");
const http = require("http");

const getRootHandler = response => ({
  handler() {
    return response;
  },
  method: "GET",
  path: "/"
});
const listener = http.createServer();
const port = 3000;
const request = () =>
  new Promise((resolve, reject) => {
    const req = http.request(
      {
        hostname: "0.0.0.0",
        port,
        method: "GET",
        path: "/"
      },
      res => {
        let body = "";

        res.setEncoding("utf8");

        res.on("data", chunk => {
          body += chunk;
        });
        res.on("end", () =>
          resolve({
            body,
            headers: res.headers,
            statusCode: res.statusCode
          })
        );
      }
    );

    req.on("error", reject);
    req.end();
  });

const main = async () => {
  // Create a server
  const server1 = hapi.Server({
    autoListen: false,
    listener
  });

  // Register a `/` route that responds with "Server 1"
  server1.route(getRootHandler("Server 1"));

  // Start the `hapi.Server` and `http.Server`
  await Promise.all([
    server1.start(),
    new Promise(resolve => listener.listen(port, resolve))
  ]);

  // Check server1's response
  const { body: body1, statusCode: statusCode1 } = await request();

  assert.equal(statusCode1, 200);
  assert.equal(body1, "Server 1");
  console.log("server1 response good")

  // Stop the server. This also appears to stop `listener`
  await server1.stop();

  // Create a new server and set its listener to the same `http.Server`
  const server2 = hapi.Server({
    autoListen: false,
    listener
  });

  // Register a `/` route that responds with "Server 2"
  server2.route(getRootHandler("Server 2"));

  // Start everything
  await Promise.all([
    server2.start(),
    new Promise(resolve => listener.listen(port, resolve))
  ])

  // Check server2's response
  const { body: body2, statusCode: statusCode2 } = await request();

  assert.equal(statusCode2, 200);
  assert.equal(body2, "Server 2");
  console.log("server2 response good")

  await server2.stop();
};

main()
  .then(() => console.log("All good!"))
  .catch(error => {
    console.error(error);
    process.exit(1);
  });

Seeing this throw along with an unhandled rejection:

node hapi-listener-assertions.js
server1 response good
(node:2443) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
    at ServerResponse.setHeader (_http_outgoing.js:482:11)
    at Object.internals.writeHead (/Users/creed/Projects/hapijs/hapi/lib/transmit.js:326:21)
    at Object.internals.transmit (/Users/creed/Projects/hapijs/hapi/lib/transmit.js:105:15)
    at Object.internals.fail (/Users/creed/Projects/hapijs/hapi/lib/transmit.js:68:22)
    at processTicksAndRejections (internal/process/task_queues.js:86:5)
(node:2443) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:2443) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
{ AssertionError [ERR_ASSERTION]: 'Server 1' == 'Server 2'
    at main (/Users/creed/Projects/hapijs/hapi/hapi-listener-assertions.js:90:10)
    at processTicksAndRejections (internal/process/task_queues.js:86:5)
  generatedMessage: true,
  name: 'AssertionError [ERR_ASSERTION]',
  code: 'ERR_ASSERTION',
  actual: 'Server 1',
  expected: 'Server 2',
  operator: '==' }