How to end async mocha test inside a then() - mocha.js

Question

I need to perform two consecutive POSTs in my test, and so I have the second nested in a callback inside of a then(). When I try running my test, I get this error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
Here is my code:
it('it should not create a user with a username already in the database', (done) => {
let user = {
"username": "myusername",
"password": "password"
};
chai.request(server)
.post('/user')
.send(user)
.then((response) => {
chai.request(server)
.post('/user')
.send(user)
.then((res) => {
res.should.have.status(406);
done();
});
});
});
I've tried increased my timeout limit, and that didn't work. What am I missing here?

Answer 1

You should always have a .catch.
.then(response => ...)
.catch(e => assert.equal(e.message, "Expecting data"))

Answer 2

Mocha supports promises, and it's best to use that support if you're testing promise-based code:
it('it should not create a user with a username already in the database', () => {
let user = {
"username": "myusername",
"password": "password"
};
return chai.request(server)
.post('/user')
.send(user)
.then((response) => {
return chai.request(server)
.post('/user')
.send(user)
.then(() => {
// We're _expecting_ a promise rejection, so throw if it resolves:
throw Error('should not be reached');
}, res => {
res.should.have.status(406);
});
});
});
Otherwise, the following may happen: the assertion (res.should.have.status(406)) may fail, which throws an error, which causes done never to get called, causing a timeout.
You can catch that assertion error with .catch and call done with the error, but you have to do that for all your tests, which is a bit tedious. It's also error-prone, because if, for some reason, a new error gets thrown inside the .catch, you end up with the same problem.

Answer 3

Ok, I figured it out. Found the answer on this post: When testing async functions with Mocha/Chai, a failure to match an expectation always results in a timeout
The reason it was never hitting my done calls was that it was hitting an uncaught exception and never returning. I wasn't providing a failure callback inside of my thens, and the Not Acceptable exception was being thrown.
Here is my fixed code:
it('it should not create a user with a username already in the database', (done) => {
let user = {
"username": "anh",
"password": "pass"
};
chai.request(server)
.post('/user')
.send(user)
.then((response) => {
chai.request(server)
.post('/user')
.send(user)
.then(() => {
throw Error('Something went wrong');
},
(res) => {
res.should.have.status(406);
done();
});
},
(res) => {
throw Error('Something went wrong');
});
});