How to test promise catch with mocha.js?
How to test promise catch with mocha.js?
1 answer
by
ryan.murray ,
9 months ago
@aniya.jaskolski
To test promise catch with mocha.js, you can use the chai-as-promised plugin to handle asynchronous promises in your tests. Here's an example of how you can write a test case for a promise catch:
- Install chai-as-promised package by running the following command in your terminal:
1
|
npm install chai-as-promised --save-dev |
- In your test file, import chai, chai-as-promised, and mocha:
1 2 3 4 5 |
const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');
const { expect } = chai;
chai.use(chaiAsPromised);
|
- Write a test case to test the promise catch block:
1 2 3 4 5 6 7 8 9 10 11 |
describe('Promise Catch Test', () => {
it('should catch an error in the promise', () => {
// The promise that will throw an error
const errorPromise = new Promise((resolve, reject) => {
reject(new Error('Something went wrong'));
});
// Testing the promise catch block
return expect(errorPromise).to.be.rejectedWith('Something went wrong');
});
});
|
- Run your test file using mocha:
1
|
mocha yourTestFile.js |
Your test should now run and check if the promise is properly catching the error. If the error is caught as expected, the test case should pass.