Package Exports

snapshot-context

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (snapshot-context) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

snapshot-context

yarn add -D -E snapshot-context

snapshot-context is an Art Deco Node.js npm package.

A context for zoroaster which enables snapshot testing.

`import snapshotContext from 'snapshot-context'`

The snapshot context should be passed in to a [Zoroaster test suite][2] in the context property.

import { fork } from 'spawncommand'
import context from '../context'
import snapshotContext from 'snapshot-context'
// import types
import { Context } from '../context' // eslint-disable-line
import { SnapshotContext } from 'snapshot-context' // eslint-disable-line

/** @type {Object.<string, (ctx: Context, snapshotCtx: SnapshotContext)>} */
const T = {
  context:[
    context,
    snapshotContext,
  ],
  async 'produces correct output'({ TEST_SUITE_PATH }, { test, setDir }) {
    setDir(SNAPSHOT_DIR)
    const { promise } = fork(BIN, [TEST_SUITE_PATH, '--babel'], {
      stdio: 'pipe',
    })
    const { stdout } = await promise
    await test('integration-stdout.txt', s)
  },
}

export default T

API

There are a set of methods made available by the api.

setDir(path:string)

Sets the root directory to save to and read snapshots from. Otherwise, an absolute path to the file can be passed.

import { resolve } from 'path'
import snapshotContext, { SnapshotContext } from 'snapshot-context' // eslint-disable-line
import erte from '../../src' // tested lib

const SNAPSHOT_DIR = resolve(__dirname, '../snapshot')

const stringContext = {
  /**
   * A string with 1 new line
   */
  s: 'I am all in a sea of wonders.\nI doubt;\nI fear;\n',
  /**
   * A string with 2 new lines
   */
  t: 'I am all in a sea of wonders.\n\nI doubt;\n\nI fear;\n\n',
}

/** @type {Object.<string, (ctxString: stringContext ctx: SnapshotContext)>} */
const T = {
  context: [
    function () {
      Object.assign(this, stringContext)
    },
    snapshotContext,
  ],
  async 'replaces new lines'({ s, t }, { setDir, test }) {
    setDir(SNAPSHOT_DIR)
    const res = erte(s, t)
    await test('new-lines.txt', res)
  },
  // absolute path without set-dir
  async 'replaces reverse new lines'({ s, t }, { test }) {
    const res = erte(t, s)
    const path = resolve(SNAPSHOT_DIR, 'new-lines-reverse.txt')
    await test(path, res)
  },
}

export default T

async test(path:string, actual: string|object)

Test whether a snapshot matches the one saved in the path. An equality of strings is asserted, and objects are deep-equal tested. Objects are serialised as JSON for writing, and back when reading.

If there's no snapshot file existing, the user is prompted to answer the save snapshot question with a y to confirm new snapshot.
The path to the file will be ensured, so that all directories in the path are made.
The error stack will start at the point where test is called.

test cli demo

The difference between objects will be shown using deepEqual from the assert-diff

object diff

The difference between strings will be highlighted with erte.

string diff