CODEWITHSUNDEEP
unit-testingcoffeescriptpromisemocha.jschai
Иво Стратев
Иво Стратев

Reputation: 415

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()

Upvotes: 0

Views: 99

Answers (2)

Иво Стратев
Иво Стратев

Reputation: 415

Yea I found that the hard way, any way I found how to test my code. I wasn't mocking my mongoose DB model right by using proxyquire. Using proxyquire.noCallThru() beforeEach and proxyquire.callThru() afterEach fixed my issue wich in fact was that I had never actually mocked my model since it required mongoose ...

Upvotes: 0

robertklep
robertklep

Reputation: 203359

The issue is that for your last test, the code will never get to calling done() because the assertion before it will fail and throw an exception.

Since Mocha has built-in support for promises, you can rewrite your tests accordingly (without the done callback):

it "simply calls done()", () ->
  return session.ready()

it "make a fail assertion", () ->
  return session.ready().then ->
    expect(3).to.equal(4)

Upvotes: 2

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