snapshot-context


snapshot-context is Context For Snapshot Testing In _Zoroaster_.

``sh
yarn add -DE snapshot-context
`

>Since Zoroaster 3.8.5, the snapshot functionality is enabled by returning the result of the test, there's no need to install this package manually.

Table Of Contents

- Table Of Contents
- class SnapshotContext
- API
* setDir(path:string)
* async test(path:string, actual: string|object)
- Copyright & License





class SnapshotContext

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

`js
import { fork } from 'spawncommand'
import SnapshotContext from 'snapshot-context'
import Context from '../context'

/**
@type {Object.} /
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 is a set of methods made available by the API.





$3

Sets the root directory to save to and read snapshots from. Otherwise, an absolute path to the file can be passed. By default, the test/snapshot directory is used.

`js
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.} /
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
`





$3

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

Copyright & License

GNU Affero General Public License v3.0

alt="Art Deco">	© Art Deco™ for ContextTesting 2020