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https://github.com/onechiporenko/chai-assertions-count
Plugin for ChaiJS allows checking how many assertions or expects were run per each test.
https://github.com/onechiporenko/chai-assertions-count
Last synced: about 1 month ago
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Plugin for ChaiJS allows checking how many assertions or expects were run per each test.
- Host: GitHub
- URL: https://github.com/onechiporenko/chai-assertions-count
- Owner: onechiporenko
- License: mit
- Created: 2022-03-12T18:31:39.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2024-03-22T08:43:32.000Z (8 months ago)
- Last Synced: 2024-04-22T12:05:54.927Z (7 months ago)
- Language: JavaScript
- Homepage:
- Size: 48.8 KB
- Stars: 1
- Watchers: 3
- Forks: 0
- Open Issues: 10
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Chai Assertions Count
[](https://github.com/onechiporenko/chai-assertions-count/actions/workflows/ci.yml)
[](http://badge.fury.io/js/chai-assertions-count)
[](https://www.npmjs.com/package/chai-assertions-count)
[](http://doge.mit-license.org)
> Plugin for ChaiJS allows checking how many assertions or expects were run per each test.
## Why do we need to check it?
Let's look at the test:
```js
import InstanceGenerator from '../lib/instances-generator';
describe('suite #1', () => {
it('test #1', () => {
class S1T1A {
/* Other props and methods are skipped */
/**
* I'm called after any instance of S1T1A is created
*/
afterCreate(...args) {
// I need to check `args` here
// chai.expect(args)...
}
}
InstanceGenerator.create(S1T1A, 3); // create 3 instances of S1T1A
});
});
```
Test looks pretty dummy, but its main idea that it's not possible to figure out was `afterCreate` called or not without dummy flag. It must be initialized on the top of the test. Then it must be toggle inside `afterCreate` and another `expect` must be added at the end of the test.
Tests becomes less readable.
Better way is to check how many `expect` were done.
## Install
```shell
npm i -D chai-assertions-count
```
or
```shell
yarn add -D chai-assertions-count
```
## Plugin
Use this plugin as you would all other Chai plugins.
```js
const chai = require('chai');
const chaiAssertionsCount = require('chai-assertions-count');
chai.use(chaiAssertionsCount);
```
## Usage
```js
const chai = require('chai');
const chaiAssertionsCount = require('chai-assertions-count');
chai.use(chaiAssertionsCount);
describe('suite #2', () => {
beforeEach(() => {
chai.Assertion.resetAssertsCheck();
});
afterEach(() => {
// you don't need both of them
chai.Assertion.checkAssertionsCount();
chai.Assertion.checkExpectsCount();
});
});
```
Method `resetAssertsCheck` just drops internal counters and **must** be used before each test.
Method `checkExpectsCount` calculated how many times `chai.expect` was called. Use it in case when your tests use [Expect](https://www.chaijs.com/guide/styles/#expect) style.
Method `checkAssertionsCount` calculated how many assertions were done. Main difference between this method and previous one is that single `expect` may do more than one `assertion`. Example below illustrates this:
```js
const chai = require('chai');
const chaiAssertionsCount = require('chai-assertions-count');
chai.use(chaiAssertionsCount);
describe('suite #3', () => {
it('test #1', () => {
chai.Assertion.expectAssertions(3);
chai.Assertion.expectExpects(2);
chai.expect(1).to.be.equal(1);
chai.expect([]).to.have.property('length', 0);
});
});
```
Here are **two** expects and we "expect" that two of them will be executed. In the same time there are **three** assertions "under the hood". First `expect` has a single assertion. However, second `expect` has two of them. First one checks that property `length` exists and another one checks its value. So, be aware with `expectAssertions` counter.
Method `expectExpects` can cover most cases, so `expectAssertions` won't be used in 99.9%.
## Restrictions
* Works only with [Expect](https://www.chaijs.com/guide/styles/#expect) style.
* Stop other tests in the current suite on `expectExpects` or `expectAssertions` fail.