Mocha unit test for Promise throws error - node.js

Question

I'm trying to unit test a promise. Here is the code :
it('it should return some 10 user data with ok status code when called with url ', (done) => {
return user.getUsers('https://jsonplaceholder.typicode.com/users')
.then((response) => {
console.log('me here')
assert.equal(JSON.parse(response).length, 10)
})
.catch((err)=>{
console.log('me in error')
assert.fail('err')
})
})
The above code when run throws the following error :
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves. (C:\Users\ajay\jay-workspace\UniTestModule\test\user.test.js)

Answer 1

done isn't called, this results in test timeout.
Mocha natively supports promises. done shouldn't be used when there are promises; instead, promises should be returned:
it('it should return some 10 user data with ok status code when called with url ', () => {
return user.getUsers('https://jsonplaceholder.typicode.com/users')
.then((response) => {
console.log('me here')
assert.equal(JSON.parse(response).length, 10)
});
})
Rejected promise will fail the test, no need for assert.fail as well.

Answer 2

You should call done() callback when using async testing (for details check https://mochajs.org/#asynchronous-code).
it('it should return some 10 user data with ok status code when called with url ', (done) => {
user.getUsers('https://jsonplaceholder.typicode.com/users')
.then((response) => {
console.log('me here')
assert.equal(JSON.parse(response).length, 10);
done();
})
.catch((err)=>{
console.log('me in error')
assert.fail('err');
done(err);
})

Answer 3

You should use --timeout hook and increase the number of ms like ./node_module/.bin/mocha test/ --timeout=5000
OR you can add this.timeout(5000) in the test case body
it('it should return some 10 user data with ok status code when called with url ', (done) => {
user.getUsers('https://jsonplaceholder.typicode.com/users')
.then((response) => {
console.log('me here')
assert.equal(JSON.parse(response).length, 10);
this.timeout(5000);
setTimeout(done, 3000);
})
https://mochajs.org/#test-level