AssertionError [ERR_ASSERTION]：子进程配置错误

Question

我有一个test.js文件，它接收一个child_process并检查环境变量MY_ENV_VAR，这是在index.js文件练习函数中设置的。当我运行node test.js时，测试失败，出现一个错误，即AssertionError ERR_ASSERTION:子进程配置错误。我试过调试，但没有得出任何可靠的结论。我认为子进程没有接收到正确的output.Below是本练习所需的文件：

其他信息

我将额外的命令添加到派生方法中，这些命令反映在下面的index.js文件中。这现在会导致另一个断言错误，因为我的环境变量的长度不等于assertion.strictEqual在child.js文件中指定的一个。子进程正在接收系统环境变量，而不是相对于此进程的环境变量。因此，如果我可以限制环境变量的范围，那么程序将按预期工作。

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index.js

'use strict'
const { spawn } = require('child_process')

function exercise (myEnvVar) {
  // TODO return a child process with
  // a single environment variable set 
  // named MY_ENV_VAR. The MY_ENV_VAR 
  // environment variable's value should 
  // be the value of the myEnvVar parameter 
  // passed to this exercise function
  process.env.MY_ENV_VAR = myEnvVar
  return spawn(process.execPath, 
['child.js', '-e','process.env',
 '-e', 'process.stdout.pipe(process.stdout)', '-e', 'process.exit(0)']);
}
module.exports = exercise

child.js

'use strict'
const assert = require('assert')
const clean = (env) => Object.fromEntries(
  Object.entries(env).filter(([k]) => !/^(_.*|pwd|shlvl)/i.test(k))
)
const env = clean(process.env)

assert.strictEqual(env.MY_ENV_VAR, 'is set')
assert.strictEqual(
  Object.keys(env).length,
  1,
  'child process should have only one env var'
)
console.log('passed!')

test.js

'use strict'
const assert = require('assert')
const { equal } = assert.strict
const exercise = require('.')

let sp = null
try {
  sp = exercise('is set')
  assert(sp, 'exercise function should return a child process instance')
  if (Buffer.isBuffer(sp)) {
    equal(sp.toString().trim(), 'passed!', 'child process misconfigured')
    process.stdout.write(sp)
    return
  }
} catch (err) { 
  const { status} = err
  if (status == null) throw err
  equal(status, 0, 'exit code should be 0')
  return
}

if (!sp.on) {
  const { stdout, stderr } = sp
  if (stderr.length > 0) process.stderr.write(stderr)
  if (stdout.length > 0) process.stdout.write(stdout)
  equal(sp.status, 0, 'exit code should be 0')
  equal(stdout.toString().trim(), 'passed!', 'child process misconfigured')
  return
}

let out = ''
if (sp.stderr) sp.stderr.pipe(process.stderr)
if (sp.stdout) {
  sp.stdout.once('data', (data) => { out = data })
  sp.stdout.pipe(process.stdout)
} else {
  // stdio may be misconfigured, or fork method may be used,
  // allow benefit of the doubt since in either case
  // exit code check will still fail:
  out = 'passed!'
}
const timeout = setTimeout(() => {
  equal(out.toString().trim(), 'passed!', 'child process misconfigured')
}, 1000)

sp.once('exit', (status) => {
  equal(status, 0, 'exit code should be 0')
  equal(out.toString().trim(), 'passed!', 'child process misconfigured')
  clearTimeout(timeout)
})

所有的帮助都是欢迎和感谢的

Answer 1

我已经更新了index.js中的函数，并且代码执行时有与会者参加。正确的解决办法如下：

index.js

'use strict'
const { spawn } = require('child_process')

function exercise (myEnvVar) {
  // TODO return a child process with
  // a single environment variable set 
  // named MY_ENV_VAR. The MY_ENV_VAR 
  // environment variable's value should 
  // be the value of the myEnvVar parameter 
  // passed to this exercise function
  return spawn(process.execPath, ['child.js'], {
    env: {MY_ENV_VAR: myEnvVar}
  });
}
module.exports = exercise

Answer 2

我相信我和你做的项目是一样的。请注意，我们无法在的Node.js版本16上使用以下代码清除子进程的环境变量。(不过，它在Linux上运行得很好)

function exercise (myEnvVar) {
  // TODO return a child process with
  // a single environment variable set 
  // named MY_ENV_VAR. The MY_ENV_VAR 
  // environment variable's value should 
  // be the value of the myEnvVar parameter 
  // passed to this exercise function
  return spawn(process.execPath, ['child.js'], {
    env: {MY_ENV_VAR: myEnvVar}
  });
}