mocha-chai-snapshot

Hook for chai to generate and matche snapshot in testing node application just like in jest

Getting Started

Install mocha-chai-snapshot using npm:

1npm install --save-dev mocha-chai-snapshot

Example Useage

1// first.spec.js  => The first file test-runner executes or add these below lines at the top of every spec file
2const chai = require('chai');
3const chaiSnapshot = require('mocha-chai-snapshot');
4const { expect } = chai;
5chai.use(chaiSnapshot);
6
7
8//component.spec.js
9describe("GET /hello", () =>{
10    it("Should say Hello to Starnger", () => {
11        return request(app)
12        .get('/hello')
13        .set('Accept', 'application/json')
14        .expect('Content-Type', /json/)
15        .expect(200)
16        .then(({ body }) => {
17            expect(body).to.matchSnapshot(this);
18        });
19    });
20
21    it("Should say Hello to Jhon", () => {
22        return request(app)
23        .get('/hello')
24        .query({ name: 'Jhon' })
25        .set('Accept', 'application/json')
26        .expect('Content-Type', /json/)
27        .expect(200)
28        .then(({ body }) => {
29            expect(body).to.matchSnapshot(this);
30        });
31    });
32});

It will automatically create(if CHAI_SNAPSHOT_UPDATE environment variable to true) __snapshots__ folder in same folder of specs and snapshot file like below

1exports[`GET /hello : Should say Hello to Starnger 1`] = "Hello, stranger!";
2exports[`GET /hello : Should say Hello to Jhon 1`] = {
3  "name": "Jhon",
4  "say": "Hello"
5};

If the found snapshot does not match with the actuals and you want to update the related snapshots, use isForced in expect chain.

Example Useage

1// first.spec.js  => The first file testrunner executes or add these below lines at the top of every spec file
2const chaiSnapshot =require('mocha-chai-snapshot');
3
4chai.use(chaiSnapshot);
5
6
7//component.spec.js
8it("Should say Hello", () => {
9    return request(app)
10      .get('/hello')
11      .query({ name: 'Jack' })
12      .set('Accept', 'application/json')
13      .expect('Content-Type', /json/)
14      .expect(200)
15      .then(({ body }) => {
16        expect(body).isForced.to.matchSnapshot(this);
17      });
18});

Or

Set CHAI_SNAPSHOT_UPDATE = true to update the snapshots if there is any mismatch in any of the spec files even if isForced is not used.

Warning!: Do not set CHAI_SNAPSHOT_UPDATE = true in build pipeline. If it is set, build will never fail even if there is no snapshots available in the __snapshots__ folder.

Notes: It is tested in mocha v5.2.0 and chai v4.2.0.