Couple of Meteor tasks. Create test and make an async function sync

I'm working in a meteor project and I have problems with two tasks. 1. A function has several chained callbacks. The deeper one asynchronously creates an object and push it into an array. I want the function to return the array full of objects. Currently it is returned empty because the filling is done async. 2. I have a function I want to test so I need to create a tinytest for it. I would like someone who could help me with these issues. Please in your proposals write down the total estimated cost of this job.