Mocha unit testing Promises (I think my case is specific)

I was bumping my had against a wall whit unit testing class method that returns promise. So I tried to comment the logic and simply make the method to return new Promise that calls resolve. Still no luck ... So When I pass a function that simply calls done() to .then all is ok. But when I pass function that tests if 3 is 4 and then calls done() it timeouts.

This is my "promise" method:

class Session
  constructor: (@ip) ->
    @map = []
    @get = {}
  add: (doc, index = -1) ->
    @get[doc.key] = JSON.parse doc.value
    if index is -1
      @map.push doc
    else
      @map[index] = doc
  ready: ->
    new Promise (resolve, reject) -> resolve()
      #store.find ip: @ip, (err, docs) =>
      #  if successful err, docs then resolve()
      #  else reject err
  ....

And this are my 2 unit tests (first passes, second exeeds time limit) :

    describe "ready", ->
      session = undefined
      beforeEach ->
        Session = proxyquire "./../Session", "./sessionModel":mockSessionModel
        session = new Session "ip"
      it "simply calls done()", (done) ->
        session.ready().then -> done()
      it "make a fail assertaion", (done) ->
        session.ready().then ->
          expect(3).to.equal(4)
          done()