A simple integration test file

fixtures.js

'use strict';

let Promise = require('bluebird');
let db = require('../config/knexfile')[process.env.NODE_ENV];
let knex = require('knex')(db);


/**
 * Loads fixture data. Expects fixture data to be exported by a file in the
 * ./fixtures/ directory (e.g. ./fixtures/users.js).
 *
 * @param  {string[]} fixtures A list of fixtures to load. Must match the file
 *                             without the .js extension. For example, a value
 *                             of ['users', 'tokens'] would load data from
 *                             users.js and tokens.js.
 * @return {Promise} A promise
 */
exports.load = function(fixtures) {
    console.log('init load');
    return Promise.resolve(fixtures)
        .each(function(fixture) {
            console.log('loading %s', fixture);
            // eslint-disable-next-line global-require
            let records = require('./fixtures/' + fixture);

            // Just in case a test failed and exports.clear didn't get called,
            // delete the table contents before insering fixtures.
            return knex(fixture).del()
                .then(function() {
                    return knex.insert(records).into(fixture);
                });
        })
        .catch(function(err) {
            console.log(err);
        });
};


/**
 * Deletes fixture data. Expects fixture data to be exported by a file in the
 * ./fixtures/ directory (e.g. ./fixtures/users.js).
 *
 * @param  {string[]} fixtures A list of fixtures whose data should be deleted.
 *                             Must match the file without the .js extension.
 *                             For example, a value of ['users', 'tokens'] would
 *                             load data from users.js and tokens.js.
 * @return {Promise} A promise
 */
exports.clear = function(fixtures) {
    return Promise.resolve(fixtures)
        .map(function(fixture) {
            return knex(fixture).del();
        });
};

users.js

/* eslint-disable max-nested-callbacks, no-shadow */
'use strict';

let sinon = require('sinon');
let clock = null;
let fixtures = require('../fixtures');
let data = [
    'users',
    'tokens'
];

describe('USER & AUTHENTICATION ENDPOINTS', function() {
    beforeEach(function() {
        // clock = sinon.useFakeTimers();
        // return;
        return fixtures.load(data);
    });
    afterEach(function() {
        // clock.restore();
        // return;
        return fixtures.clear(data);
    });


    context('POST /users', function() {
        it('should prevent the creation of a user with an existing email address', function(done) {
            done();
        });
    });
});

The before|afterEach() work fine as written above. They also work when written as:

    beforeEach(function() {
        clock = sinon.useFakeTimers();
        return;
        // return fixtures.load(data);
    });
    afterEach(function() {
        clock.restore();
        return;
        // return fixtures.clear(data);
    });

In the case below, the beforeEach() works, but the afterEach() does not:

    beforeEach(function() {
        // clock = sinon.useFakeTimers();
        // return;
        return fixtures.load(data)
            .then(function() {
                clock = sinon.useFakeTimers();
                return true;
            });
    });
    afterEach(function() {
        // clock.restore();
        // return;
        return fixtures.clear(data)
            .then(function() {
                clock.restore();
                return true;
            });
    });

If I follow through on the promise returned from fixtures.load(), I can get through the beforeEach() and run the test:

    beforeEach(function() {
        return fixtures.load(data)
            .then(function() {
                clock = sinon.useFakeTimers(new Date().getTime());
                return;
            });
    });

However, even after updating the afterEach() in a similar manner the timeout still occurs in that callback:

    afterEach(function() {
        return fixtures.clear(data)
            .then(function() {
                // clock.restore();
                return;
            });
    });

I'll leave this thread with a link to the Knex issue that helped me resolve this: knex/knex#1267 (comment).