The jest-specific-snapshot package allows you to create and manage Jest snapshots in a more granular and specific manner. It provides functionality to create snapshots for specific tests and manage them independently, which can be useful for large test suites or when you need more control over your snapshot testing.

What are jest-specific-snapshot's main functionalities?

Creating a specific snapshot

This feature allows you to create a snapshot for a specific test and store it in a specified file. This can be useful for organizing snapshots and keeping them separate from other tests.

const { toMatchSpecificSnapshot } = require('jest-specific-snapshot');
expect.extend({ toMatchSpecificSnapshot });

test('example test', () => {
  const data = { key: 'value' };
  expect(data).toMatchSpecificSnapshot('./__snapshots__/example.snap');
});

Updating a specific snapshot

This feature allows you to update an existing snapshot for a specific test. If the snapshot already exists, it will be updated with the new data provided in the test.

const { toMatchSpecificSnapshot } = require('jest-specific-snapshot');
expect.extend({ toMatchSpecificSnapshot });

test('example test', () => {
  const data = { key: 'new value' };
  expect(data).toMatchSpecificSnapshot('./__snapshots__/example.snap');
});

Other packages similar to jest-specific-snapshot

Readme

Source

Jest Specific Snapshot

Jest matcher for multiple snapshot files per test

You can read about the implementation here

Installation

npm i -D jest-specific-snapshot

Example

const path = require('path');
// extend jest to have 'toMatchSpecificSnapshot' matcher
require('jest-specific-snapshot');

test('test', () => {
  // provides snapshot file with absolute file
  const pathToSnap = path.resolve(process.cwd(), './example/specific/dir/my.shot');
  expect(100).toMatchSpecificSnapshot(pathToSnap);

  //same snapshot but with relative file
  expect(14).toMatchSpecificSnapshot('./specific/dir/my.shot');

  // another snapshot file in the same test
  expect(19).toMatchSpecificSnapshot('./specific/another_dir/another.shot');
});

With Custom Serializer

// extend jest to have 'toMatchSpecificSnapshot' matcher
const addSerializer = require('jest-specific-snapshot').addSerializer;

addSerializer(/* Add custom serializer here */);

test('test', () => {
  expect(/* thing that matches the custom serializer */).toMatchSpecificSnapshot(
    './specific/custom_serializer/test.shot'
  );
});

Extend `toMatchSpecificSnapshot`

const toMatchSpecificSnapshot = require('jest-specific-snapshot').toMatchSpecificSnapshot;

expect.extend({
  toMatchDecoratedSpecificSnapshot(received, snapshotFile) {
    // You can modify received data or create dynamic snapshot path
    const data = doSomeThing(received);
    return toMatchSpecificSnapshot.call(this, data, snapshotFile);
  },
});

Limitations

Snapshot files should have an extension other than .snap, since it conflicts with jest.
In order to handle the --updateSnapshot (-u) parameter provided from CLI, there is an abuse of the SnapshotState._updateSnapshot private field. TBD - try to use the globalConfig to get this state.
.toMatchSpecificSnapshot does ignore a custom serializers strategy. In order to support custom serializers, you should use the addSerializer method explicitly.

FAQs

What is jest-specific-snapshot?

Is jest-specific-snapshot well maintained?

Package last updated on 05 Mar 2023

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