 
       _fn = (args) ->
         diff = Date.now() - start
-        diff.should.be.within output[i], output[i] + 7
+        diff.should.be.approximately output[i], 10
         if i is output.length - 1 then complete()
         i++
 

      last = now

      if diff isnt Infinity
        diff.should.be.within duration, duration + 10

      switch count++



    promise.then ->
      diff = Date.now() - start
      diff.should.be.approximately duration, 10
      done()


