test.js

(async () => {
  const test = await new Promise((resolve) => {
    console.log('test1');
    process.on('message', (message) => {
      resolve(message.payload);
    });
    console.log('test2');

    if (process.send !== undefined) {
      process.send('');
      console.log('test4');
    }
    console.log('test3');
  });

  console.log('test5');
})().then(() => console.log('finished'));