Stdstream-snapshot NPM

@qiwi/stdstream-snapshot

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

Install

yarn add @qiwi/stdstream-snapshot -D
npm add @qiwi/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 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 are 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