block when simulate user input

[supperchong]

• Version: node v12.13.0
• Platform: 64-bit (Windows)
• Subsystem: cmd/PowerShell

Sometimes, we want to simulate user input , for example we need test when we write a npm module.
like following code ,it will block at the second prompt , can't see the second question.

const inquirer = require('inquirer');
const choices = [
    {
        name: "test1",
        value: "test1"
    },
    {
        name: "test2",
        value: "test2"
    }
];
const choices2 = [
    {
        name: "test1",
        value: "test1"
    },
    {
        name: "test2",
        value: "test2"
    }
];
(async ()=>{
  let p1= inquirer.prompt({
    name: 'boilerplateInfo',
    type: 'list',
    message: 'Please select a boilerplate type',
    choices: choices2,
    pageSize: choices2.length,
  });

  //it will block
  setTimeout(()=>{
    process.stdin.emit('keypress','\r') 
  },100)
  
  await p1

  await inquirer.prompt({
    name: 'boilerplateInfo',
    type: 'list',
    message: 'Please select a boilerplate type',
    choices: choices2,
    pageSize: choices2.length,
  });
})()

look at source code, when one prompt over, the readline instance will pause process.stdin before close , It works good when it's interacting with the reality user. Moreover pause process.stdin is to fix the similar bug , issues: Make inquirer.prompt() blocking, Fix bug to properly close readline, readline: pause stdin before turning off terminal raw mode

But when we want to simulate user input, it block. I find some solution, but i don't know the reason.
My problem is what's the right way to simulate user input ?

And I find some strange problems with readline.close .Maybe these are node bugs. Inquirer prompt use different readline instance to hanlde questions. I know you intend refactor inquirer . Consider if use one readline instance ? @SBoudrias

1. solution one：resume process.stdin after close and wait a little time

const inquirer = require('inquirer');
const inquirer = require('inquirer');
const choices = [
    {
        name: "test1",
        value: "test1"
    },
    {
        name: "test2",
        value: "test2"
    }
];
const choices2 = [
    {
        name: "test1",
        value: "test1"
    },
    {
        name: "test2",
        value: "test2"
    }
];
function sleep(time) {
    return new Promise(resolve => {
        setTimeout(resolve, time);
    });
}
(async () => {
    let p1 = inquirer.prompt({
        name: 'boilerplateInfo',
        type: 'list',
        message: 'Please select a boilerplate type',
        choices: choices2,
        pageSize: choices2.length,
    });
    setTimeout(() => {
        p1.ui.rl.input.emit('keypress', '\r')
    }, 100)
    await p1.then(() => p1.ui.rl.input.resume())
    await sleep(10) //this is neccessary
    let p2 = inquirer.prompt({
        name: 'boilerplateInfo',
        type: 'list',
        message: 'Please select a boilerplate type',
        choices: choices2,
        pageSize: choices2.length,
    });
    process.stdin.emit('keypress', '\r')
})()

2. solution two: emit keypress immediately

const choices = [
    {
        name: "test1",
        value: "test1"
    },
    {
        name: "test2",
        value: "test2"
    }
];
const choices2 = [
    {
        name: "test1",
        value: "test1"
    },
    {
        name: "test2",
        value: "test2"
    }
];
const inquirer = require('inquirer');
(async () => {
    let p1 = inquirer.prompt({
        name: 'boilerplateInfo',
        type: 'list',
        message: 'Please select a boilerplate type',
        choices: choices2,
        pageSize: choices2.length,
    });
    // setTimeout(() => {
    process.stdin.emit('keypress', '\r')
    // }, 100)
    await p1
    let p2 = inquirer.prompt({
        name: 'boilerplateInfo',
        type: 'list',
        message: 'Please select a boilerplate type',
        choices: choices2,
        pageSize: choices2.length,
    });
    process.stdin.emit('keypress', '\r')
})()