stdstream-snapshot

Util for CLI testing: fetch stdout, stderr streams and match its data to snapshot

Install

yarn add stdstream-snapshot -D
npm add stdstream-snapshot -D

Snapshot

{
  "stderr": "",
  "stdout": "/rules/some-rules.ts\n    2:7   error  'name'...",
  "err": {
    "signal": null,
    "code": 1,
    "killed": false
  }
}

Usage

With Jest:

import {generateSnapshot} from 'stdstream-snapshot'

it('cmd output matches to snapshot', async () => {
  const cmd = 'somecmd --flag=foo -b'
  const result = await generateSnapshot({
    cmd,
  })

  expect(result).toMatchSnapshot()
})

With Jasmine or another one test framework with no built-it snapshot API:

import {matchSnapshot} from 'stdstream-snapshot'

it('cmd output matches to snapshot', async () => {
  const cmd = 'somecmd --flag=foo -b'
  const target = './test/snapshots/some-cmd-output.json'
  const result = await matchSnapshot({
    cmd,
    target,
    update: !!process.env.UPDATE_SNAPSHOT
  })

  expect(result).toBe(true)
})

Options

There're several normalization steps supported out of box.

Option	Description	Default
trim	Removes redundant spaces from both ends of strings	true
normalizePaths	Replaces process.cwd() prefix from any found paths in the output strings	true
normalizeSpaces	Converts tabs to double spaces	true
normalizeEncoding	Replaces output rubbish like [8m [10m	true