Error: done() invoked with non-Error: {"req":{ ......} request done without error, but test didn't pass

I'm trying to resolve my test but nothing seems to work. Currently I'm using mocha, supertest and chai, but even if request was performed successfully, I'm seeing this annoying error I can't get rid off. Can anyone help me with this? I'm stuck for days on this...

let should = require('chai').should(),
    expect = require('chai').expect,
    constants = require('./constants'),
    supertest = require('supertest'),
    api = supertest(constants.ENVIRONMENT),
    express = require('express'),
    http = require('http'),
    request = require('request'),
    app = express(),
    bodyParser = require('body-parser'),
    port = process.env.PORT || 3000,
    assert = require('assert');
    
    describe('Create device API call', () => {

    function createToken() {
        return new Promise(resolve =>
            request.post(
                'myURl',
                { 
                 json: 
                        { 
                          "username": "myUsername", 
                          "password": "myPassword" 
                        } 
                },
                function (error, response, body) {
                    if (!error && response.statusCode == 200) {
                        let token = (body.accessList[0].accessToken);
                        resolve(token);

                    }
                    else {
                        console.log("Server error get token")
                    }

                })
        )
    }

    it('should create device', async (done) => {

        let token = await createToken();

        //console.log(`Token is ${token}`);

        api.post('/deviceManifests/1/devices')
            .set('Accept', 'application/json')
            .set('Authorization', `Bearer ${token}`)
            .send({
                "name": "QA integration",
                "deviceKey": "somekey38957",
                "defaultBinding": true
            })
            .expect('content-Type', /json/)
            .expect(201)
            .expect(function (res, err) {
                assert.equal(res.body.name, 'QA integration');

            }).then(done);
    });

});