Create a fake child process

fake-child-process.ts

import * as child_process from 'child_process';
import EventEmitter from 'events';
import { Readable } from 'stream';

const mockChildProcess = (): child_process.ChildProcess => {
  const proc = new EventEmitter() as child_process.ChildProcess;
  
  proc.stdout = new EventEmitter() as Readable;
  proc.stderr = new EventEmitter() as Readable;

  return proc;
};