javascript - How to do unit test in dependent modules (node.js)? -

i have application 2 modules (book , user). book model looks this:

var mongoose = require('mongoose'), schema = mongoose.schema;  var bookmodel = new schema({      name: string,     author: string,     description: string,     _user: {type: schema.types.objectid, ref: 'user'}  });  module.exports = mongoose.model('book', bookmodel); 

and user model:

var mongoose = require('mongoose'),     bcrypt = require('bcryptjs'),     schema = mongoose.schema;  var usermodel = new schema({    name: string,   username: string,   password: string,  });  module.exports = mongoose.model('user', usermodel); 

i want unit test in post method (inserting book in db) condition of not allowing empty name. have in post method:

var post = function (req, res) {     var booknew = new book(req.body);      // paylod user's token     var payload = tokenmanager.getpayload(req.headers);      if (req.body._user)         delete req.body._user;      if (!req.body.name) {         res.status(400);         res.send("name required");     } else if (payload == null || payload == undefined) {         res.status(400);         res.send("token error");     } else {         // store user id         booknew.set('_user', payload.id);          booknew.save();         res.status(201);         res.send("book saved");     } }; 

as can see, payload token (created when user logged in). because payload contains user id and, then, insert in _user (property in book model).

the problem if unit test in order verify if book’s property (name) filled, don’t have user retrieve payload. therefore, payload undefined , book unit test not successful in case. have suggestion on should do? looks have create user in order test book modules… not sure if suitable solution.