https://github.com/satya164/jest-file-snapshot

Jest matcher to write snapshots to a separate file instead of the default snapshot file used by Jest
https://github.com/satya164/jest-file-snapshot

hacktoberfest jest snapshot-testing testing

Last synced: about 2 months ago
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Jest matcher to write snapshots to a separate file instead of the default snapshot file used by Jest

• Host: GitHub
• URL: https://github.com/satya164/jest-file-snapshot
• Owner: satya164
• Created: 2018-09-29T21:44:37.000Z (almost 6 years ago)
• Default Branch: main
• Last Pushed: 2024-07-10T19:51:02.000Z (2 months ago)
• Last Synced: 2024-07-10T23:32:01.425Z (2 months ago)
• Topics: hacktoberfest, jest, snapshot-testing, testing
• Language: JavaScript
• Homepage:
• Size: 2.29 MB
• Stars: 40
• Watchers: 3
• Forks: 14
• Open Issues: 2
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

• awesome-jest - jest-file-snapshot

README

        
# jest-file-snapshot

[![Build Status][build-badge]][build]

[![Code Coverage][coverage-badge]][coverage]

[![MIT License][license-badge]][license]

[![Version][version-badge]][package]

Jest matcher to write snapshots to a separate file instead of the default snapshot file used by Jest. Writing a snapshot to a separate file means you have proper syntax highlighting in the output file, and better readability without those pesky escape characters. It's also useful if you have binary content.

## Installation

```sh

npm install --save-dev jest-file-snapshot

```

or

```sh

yarn add --dev jest-file-snapshot

```

## Usage

Extend Jest's `expect`:

```js

import { toMatchFile } from 'jest-file-snapshot';

expect.extend({ toMatchFile });

```

Then use it in your tests:

```js

it('matches content of file on disk', () => {

  expect(content).toMatchFile();

});

```

The content passed can be of type `string` or a `Buffer`. The comparison be done using `Buffer.equals()` instead of `===` if a `Buffer` is passed.

The matcher takes two optional arguments:

- `filepath`: path to the file whose content should be matched, e.g. `expect(content).toMatchFile(path.join(__dirname, 'output.md'))`

- `options`: additional options object for the matcher, with following properties:

  - `diff`: options for [`jest-diff`](https://github.com/facebook/jest/tree/master/packages/jest-diff)

  - `fileExtension`: optional file extension to use for the snapshot file.

You should also [exclude the output files from Jest's watcher](https://jestjs.io/docs/en/configuration#watchpathignorepatterns-arraystring) so that updating the snapshot doesn't re-run the tests again.

For example, by default `toMatchFile` uses a folder named `__file_snapshots__` which you can exclude by adding the following under the `jest` key in `package.json`:

```json

"watchPathIgnorePatterns": [

  "__file_snapshots__"

]

```

## Credits

- [jest-image-snapshot](https://github.com/americanexpress/jest-image-snapshot)

## Contributing

Make sure your code passes the unit tests, ESLint and TypeScript. Run the following to verify:

```sh

yarn test

yarn lint

yarn typescript

```

To fix formatting errors, run the following:

```sh

yarn lint -- --fix

```

[build-badge]: https://img.shields.io/circleci/project/github/satya164/jest-file-snapshot/main.svg?style=flat-square

[build]: https://circleci.com/gh/satya164/jest-file-snapshot

[coverage-badge]: https://img.shields.io/codecov/c/github/satya164/jest-file-snapshot.svg?style=flat-square

[coverage]: https://codecov.io/github/satya164/jest-file-snapshot

[license-badge]: https://img.shields.io/npm/l/jest-file-snapshot.svg?style=flat-square

[license]: https://opensource.org/licenses/MIT

[version-badge]: https://img.shields.io/npm/v/jest-file-snapshot.svg?style=flat-square

[package]: https://www.npmjs.com/package/jest-file-snapshot