Can't figure error with publication-collector

testing
1

So I have what I think is a pretty straight forward test with publication collector, see below:

import { CitiesCollection } from '/lib/collections/cities';
import { LocationsCollection } from '/lib/collections/locations';
import { PublicationCollector } from 'meteor/johanbrook:publication-collector';
import StubCollections from 'meteor/hwillson:stub-collections';
import faker from 'faker';

if(Meteor.isServer) {
  describe('location.categories', function() {
    it('has a publication that will list all known categories', function(done) {
      const collector = new PublicationCollector();
      collector.collect('location.categories', collections => {
        assert.typeOf(collections.locations, 'array');
        assert(collections.locations.length > 0);
        done();
      });
    })
  });
}

When I run this I get this error:

    at PublicationCollector.collect (packages/johanbrook:publication-collector/publication-collector.js:45:20)
    at Test.<anonymous> (test/publications/locations.tests.js:12:17)
    at run (packages/practicalmeteor:mocha-core/server.js:56:16)

Where am I going wrong?
Thanks.