Karma Plugin for Snapshot Testing with Mocha

Snapshot Format

Snapshot can be stored in different formats. Right now there are two formats supported: md and indented-md.

$3

This format is preferred when you specify language for code blocks in an assertion plugin. With this format, code
editors will automatically highlight syntax of code blocks.

```md


src/html.js

Sub Suite

#### HTML Snapshot

`html



`
``

$3

`md


src/html.js

Sub Suite

#### HTML Snapshot


`

Snapshot File Path

Snapshot file path is extracted from the name of the root suit cases and stored alongside with a tested files in a
__snapshots__ directory.

Snapshot file path can be changed by providing a custom pathResolver in snapshot config.

Usage Example

`sh
$ npm install karma karma-webpack karma-sourcemap-loader karma-snapshot karma-mocha \
karma-mocha-snapshot karma-mocha-reporter karma-chrome-launcher mocha \
chai chai-karma-snapshot webpack --save-dev
`

Karma configuration:

`js
// karma.conf.js
const webpack = require("webpack");

module.exports = function (config) {
config.set({
browsers: ["ChromeHeadless"],
frameworks: ["mocha", "snapshot", "mocha-snapshot"],
reporters: ["mocha"],
preprocessors: {
"/__snapshots__//*.md": ["snapshot"],
"__tests__/index.js": ["webpack", "sourcemap"]
},
files: [
"/__snapshots__//*.md",
"__tests__/index.js"
],

colors: true,
autoWatch: true,

webpack: {
devtool: "inline-source-map",
performance: {
hints: false
},
},

webpackMiddleware: {
stats: "errors-only",
noInfo: true
},

snapshot: {
update: !!process.env.UPDATE,
},

mochaReporter: {
showDiff: true,
},

client: {
mocha: {
reporter: "html",
ui: "bdd",
}
},
});
};
`

Source file:

`js
// src/index.js

export function test() {
return "Snapshot Test";
}
`

Test file:

`js
// __tests__/index.js
import { use, expect } from "chai";
import { matchSnapshot } from "chai-karma-snapshot";
import { test } from "../src/index.js";
use(matchSnapshot);

describe("src/index.js", () => {
it("check snapshot", () => {
expect(test()).to.matchSnapshot();
});
});
`

Run tests:

`sh
$ karma start
`

Update snapshots:

`sh
$ UPDATE=1 karma start --single-run
``