Meteor mocha test subscriptions

I'm currently working on writing client-side tests for my application using practicalmeteor:mocha. Therefor I need to insert a record into a mongo collection before every step.

Following the concepts of meteor, I wrote some meteor methods to insert/update/delete the records. If I want to test the expected behaviour, I assume I have to call the appropiate method (to insert a record for example) and then have to wait for the subscription to synchronize the record to the client so I can verify the insert.

I tried a few things but none of them seems to work:

describe('a topic', function() {
    beforeEach(async function(done) {
        let res = await new Promise((resolve, reject) => {
            Meteor.call('topics.createNew', function(err, res) {
                if(err) return reject(err);
                resolve(res); //res is the _id from the generated record
            });
        });

        //subscribe to single record (the one just created)
        let subscription = Meteor.subscribe('topics.details', res); 

        //i assume this runs every time the publish function calls ready and therefor is also run when the new record is published
        Tracker.autorun((computation) => {
            let count = TopicsCollection.find({}).count();
            //console.log('topic count: ' + count);                

            if(subscription.ready() && count === 1) {
                computation.stop();
                done();
            }
        });
    });
});

I logged the counted documents and had luck when i wrapped the autorun-Funktion into a Promise but in neither of both cases, done() was called causing a timeout in mocha.

I already had a look on this question but I think it doesnt really help in my situation since I wait for every possible callback and I'm working with a plain Collection and the guy in the question above uses an accounts-package.

Can anyone suggest a better/working solution for this problem?
Thanks in advance! :D