jasmine-node - How to test async code that create files asynchronously

My script create several files out of templates.

I want my test to verify that the new files are according to expected result, but the files are not ready yet.

var fs = require("fs");
var createFiles("../createFiles");
describe{...., function(){
    it(...., function(){
         createFiles.create(); //create the file async.
         var file1 = fs.readFileSync("../file1.txt"); //the created file
         ....
    }
}

by the time I read the file, It is not ready yet or inaccessible.