👀 Views: 10 💬 Answers: 1 📅 Created: 2025-06-07

mocha chai testing javascript

I'm having trouble getting my async tests to run properly using Mocha and Chai in a Node.js application. My tests are supposed to verify that promises resolve as expected, but I'm working with the following behavior: `behavior: promise was rejected with a non-behavior: undefined`. Here's a snippet of my test code: ```javascript const chai = require('chai'); const expect = chai.expect; const myAsyncFunction = require('../src/myAsyncFunction'); describe('My Async Function', function () { it('should resolve with expected value', function () { return myAsyncFunction().then(result => { expect(result).to.equal('Expected Value'); }); }); }); ``` The `myAsyncFunction` simply returns a promise that resolves after a timeout: ```javascript function myAsyncFunction() { return new Promise((resolve) => { setTimeout(() => { resolve('Expected Value'); }, 1000); }); } module.exports = myAsyncFunction; ``` What I find confusing is that when I run the tests, they unexpected result intermittently with the behavior mentioned above, especially when I run them in parallel using `mocha --parallel`. I've confirmed that the function itself works outside of the test context, and I have tried adding the `done` callback in the test, but it didn't help. I also verified that the version of Mocha I am using is 8.4.0, and Chai is at 4.3.4. Are there any known issues or best practices for testing async functions with promises in Mocha? Any guidance would be appreciated! I'm using Javascript 3.10 in this project. Any ideas what could be causing this?