Mocha: Getting error "Error: Resolution method is overspecified. Specify a callback or return a Promise; not both."

Created on 15 Mar 2017 · 6Comments · Source: mochajs/mocha

I have something simple as this.

` it("should call promise", async (done) => {

    const testPromise = new Promise((resolve, reject) => {

        setTimeout(() => {

            resolve("Hello World!");

        }, 200);
    });


    const result = await testPromise;

    done();

But I keep on getting the error " Error: Resolution method is overspecified. Specify a callback or return a Promise; not both.".

If I take out done() then the test times out.

tsconfig.json
{ "compilerOptions": { "module": "commonjs", "target": "ES6", "noImplicitAny": false, "types": ["node", "mocha","supertest"], "typeRoots": [ "./node_modules/@types" ] } }
mocha.opts
--require ts-node/register --reporter dot --watch-extensions tsx,ts test/**/*.ts

faq

Source

fbarnard

Most helpful comment

lovely found how to fix it remove done in the function param and at bottom and it works. As soon as you put the done in function param it goes haywire

fbarnard on 15 Mar 2017

👍30 ❤15 🎉14 🚀5 😄4

All 6 comments

lovely found how to fix it remove done in the function param and at bottom and it works. As soon as you put the done in function param it goes haywire

fbarnard on 15 Mar 2017

👍30 ❤15 🎉14 🚀5 😄4

Keep in mind also that async functions automatically return a promise.

ScottFreeCode on 16 Mar 2017

👍11

seems as long as you async, and as @ScottFreeCode said, it returns promise, so we just skip calling done() . works.

vickenliu on 3 May 2018

👍4 😕1

Removing done worked for me!

BEFORE:

AFTER (Works!!):

getResponse function:

QauseenMZ on 19 May 2019

👍1

I had to removed the done from the function parameter and the done() of the function call
Before

   before(async function (done) {
        user = new User({ ...});
        await user.save();
        done()
    });

After

   before(async function () {
        user = new User({ ...});
        await user.save();
    });

These works for me

kheengz on 25 Jul 2019

👍1

I am having the same problem, and I need to user done, because I need to test that my promise fails. So I catch it, and then calling done, but getting this error.

it("...", async function (done) {
  try {
    await asyncFung(...);
    done("The call should have failed")
  } catch (error) {
    if (error instanceof MyError) {
      done()
    } else {
      done(error)
    }
  }
});