TDD – Jasmine Test CoffeeScript (Settimeout) .tohaveBeenCalledwith

class @LoopObj
 constructor: ->
 loop: (interval) ->
 #do some stuff
 setTimeout( (=>@loop(interval)), interval)

describe "loop", ->
 xit "does nifty things", ->
 it "loops at a given interval", ->
 my_nifty_loop = new LoopObj
 interval = 10
 spyOn (window, "setTimeout")
 my_nifty_loop.loop(interval)
 expect(setTimeout).toHaveBeenCalledWith((-> my_nifty_loop.loop(interval)), interval)

expect(setTimeout).toHaveBeenCalledWith((-> my_nifty_loop.loop(interval)), interval)

In the process of learning Jasmine, I encountered this problem. I want a basic function to run, and then set a timeout to call myself again… simple stuff.

< /p>

class @LoopObj
 constructor: ->
 loop: (interval) ->
 #do some stuff
 setTimeout((=>@loop(interval) ), interval)

But I want to test to make sure that setTimeout is called with the correct args

describe "loop", ->
 xit " does nifty things", ->
 it "loops at a given interval", ->
 my_nifty_loop = new LoopObj
 interval = 10
 spyOn(window, "setTimeout")< br /> my_nifty_loop.loop(interval)
 expect(setTimeout).toHaveBeenCalledWith((- > my_nifty_loop.loop(interval)), interval)

I get this error: The expected spy setTimeout is called with [Function,10] but is called with [[Function,10]]

This is because the (-> my_nifty_loop.loop(interval)) function is not equal to the (=> @loop(interval)) function? Or is it related to the extra square brackets around the second [[function,10]]? What else altogther?

Where did I go wrong?

I don’t know much about CoffeeScript, but you can debug it by replacing

expect( setTimeout).toHaveBeenCalledWith((-> my_nifty_loop.loop(interval)), interval)

Same

expect(setTimeout).toHaveBeenCalledWith(jasmine.any (Function), interval)

and re-run the specification. I think if the extra square brackets disappear, then your problem is because you have two different function references. If they don’t disappear, your The LoopObj definition will have some strange things, it may be a fat arrow operator (it seems that my n00b eyes don’t need it).