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https://github.com/localvoid/chai-karma-snapshot
Chai Plugin for Snapshot Testing with Karma
https://github.com/localvoid/chai-karma-snapshot
chai karma mocha snapshot
Last synced: about 2 months ago
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Chai Plugin for Snapshot Testing with Karma
- Host: GitHub
- URL: https://github.com/localvoid/chai-karma-snapshot
- Owner: localvoid
- License: mit
- Created: 2017-07-18T07:12:17.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2020-03-24T22:43:24.000Z (almost 5 years ago)
- Last Synced: 2024-11-05T23:49:22.398Z (2 months ago)
- Topics: chai, karma, mocha, snapshot
- Language: JavaScript
- Size: 22.5 KB
- Stars: 4
- Watchers: 2
- Forks: 8
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Chai Plugin for Snapshot Testing with Karma
## Snapshot Serialization
This plugin is using the same [serialization module](https://www.npmjs.com/package/pretty-format) that is used in [Jest](http://facebook.github.io/jest/) library.
## Snapshot Format
Snapshot can be stored in different formats. Right now there are two formats supported: `md` and `indented-md`.
### Markdown Format
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
```
````
### Indented Markdown Format
```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,
prune: !!process.env.PRUNE,
},
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, assert } from "chai";
import { matchSnapshot } from "chai-karma-snapshot";
import { test } from "../src/index.js";
use(matchSnapshot);
describe("src/index.js", () => {
it("check snapshot", () => {
// 'expect' syntax:
expect(test()).to.matchSnapshot();
// 'assert' syntax:
assert.matchSnapshot(test());
});
});
```
Run tests:
```sh
$ karma start
```
Update snapshots:
```sh
$ UPDATE=1 karma start --single-run
```
Prune snapshots:
```sh
$ PRUNE=1 karma start --single-run
```
## Config
```js
function resolve(basePath, suiteName) {
return path.join(basePath, "__snapshots__", suiteName);
}
config.set({
...
snapshot: {
update: true, // Run snapshot tests in UPDATE mode (default: false)
prune: false, // Prune snapshots for removed tests (default: true)
format: "indented-md", // Snapshot format (default: md)
checkSourceFile: true, // Checks existince of the source file associated with tests (default: false)
pathResolver: resolve, // Custom path resolver
}
});
```
## Custom Snapshot Format
Snapshot config option `format` also works with custom serialization formats. Custom snapshot serializer should have
interface:
```ts
interface SnapshotSerializer {
serialize: (name: string, suite: SnapshotSuite) => string,
deserialize: (content: string) => { name: string, suite: SnapshotSuite },
}
```