How do I spy on an Angular promise chain using Jasmine

Using AngularJS, CoffeeScript and Jasmine (edited in WebStorm), I would like to unit test a chain of promises.

Lets say I have the following example service:

Angular Service

class ExampleService
    stepData: []
    constructor: (@$http) ->

    attachScopeMethod: (@scope) ->
        @scope.callSteps = => @step1().then -> @step2()

    step1: ->
        @$http.get('app/step/1').then (results) =>
            @stepData[0] = results.data
            results

    step2: ->
        @$http.get('app/step/2').then (results) =>
            @stepData[2] = results.data
            results

This service allows me to attach a the method callSteps() to the scope. This method, when called, executes a series of asynch $http calls to a 3rd party API.

To test that each step is at least called, I have written the following Jasmine spec.

Jasmine Spec

ddescribe 'ExampleService', ->

    beforeEach ->
        module 'myApp'

    beforeEach inject ($rootScope, $injector) ->
        @scope = $rootScope.$new()
        @exampleService = $injector.get 'exampleService'
        @q = $injector.get '$q'

    describe 'process example steps', ->
        beforeEach  -> 
            @exampleService.attachScopeMethod(@scope)

        it "should attach the scope method", ->
            expect(@scope.callSteps).toBeDefined()

        describe 'when called should invoke the promise chain', ->

        it "should call step1 and step2", ->
            defer = @q.defer()
            @exampleService.step1 = jasmine.createSpy('step1').andReturn(defer.promise)

            @exampleService.step2 = jasmine.createSpy('step2')

            @scope.callSteps()
            defer.resolve()

            expect(@exampleService.step1).toHaveBeenCalled()
            expect(@exampleService.step2).toHaveBeenCalled()

The results of this test is as follows:

expect(@exampleService.step1).toHaveBeenCalled() - PASS
expect(@exampleService.step2).toHaveBeenCalled() - FAIL

Can you tell me how I can get step2() to succesfully run under test?

Thank you

EDIT

@Dashu below kindly supplied the answer to the problem. The trick is to simply call scope.$apply or scope.$digest to trigger the promise chain resolution.

So here is the working test fragment.

describe 'when called should invoke the promise chain', ->
    it "should call step1 and step2", ->
        defer = @q.defer()
        defer.resolve()

        @exampleService.step1 = jasmine.createSpy('step1').andReturn(defer.promise)
        @exampleService.step2 = jasmine.createSpy('step2')

        @scope.callSteps()
        @scope.$apply()

        expect(@exampleService.step1).toHaveBeenCalled()
        expect(@exampleService.step2).toHaveBeenCalled()

try a $rootScope.$apply() before the second expect

also about defer.resolve(). i don't know if this actually resolves the promise, i think it just setups the value to return when it resolves.

so i would move that up to just underneath the $q.defer() call, before passing the promise to the andReturn()

you could do defer.resolve(true), defer.reject(false), so if you're promise will get rejected insinde callsteps, true or false will be returned

来源：https://stackoverflow.com/questions/19633028/how-do-i-spy-on-an-angular-promise-chain-using-jasmine

标签

angularjs

jasmine