chai-as-promised should.eventually.equal not passing

Question

I am trying to write a minimum working example of chai-as-promised in order to understand how it is working when testing functions that return a promise.

I have the following function:

simple.test = async (input) => {
    return input;
};

and the following test function:

chai.use(sinonChai);
chai.use(chaiAsPromised);
const { expect } = chai;
const should = chai.should();

describe('#Test', () => {
    it('test', () => {
        expect(simple.test(1)).should.eventually.equal(1);
    });
});

However, testing this results in the test not passing, but in a very long error, which is pasted here: https://pastebin.com/fppecStx

Question: Is there something wrong about the code, or what seems to be the problem here?

Answer 1

First: Your mixing expect and should. If you want to use should for assertion, you don't need expect.

Second: To tell mocha that a test is async you have to either call done, return a Promise or use async/await.

const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');
const sinonChai = require('sinon-chai');

const should = chai.should();
chai.use(sinonChai);
chai.use(chaiAsPromised);

// Function to test
const simple = {
  test: async (input) => {
    return input;
  }
}

// Test
describe('#Test', () => {
  it('test', () => {
    return simple.test(1).should.eventually.equal(1);
  });
});