Testing RxJS bufferWithTime on node.js - coffeescript

Question

I'm TDDing RxJS solution and using bufferWithTime Why does the res in example code get value [] (empty array)? Is it a problem in my code or the RxJS library? Running it on node.js v0.10.30 with rx version 2.2.27.
Following can be run in nodejs coffeescript REPL
Rx = require 'rx'
onNext = Rx.ReactiveTest.onNext
TEST_EVENT_A = { messageName: 'test_event_a', namespace: 'test' }
events = [onNext(50, TEST_EVENT_A), onNext(100, TEST_EVENT_A)]
scheduler = new Rx.TestScheduler
stream = scheduler.createHotObservable events
excludeEmpty = (event) -> console.log "Filtering...", event; event.length > 0
countValues = (event) -> console.log "Counting...", event; event.length
res = scheduler.startWithTiming((=> stream.bufferWithTime(10).filter(excludeEmpty).map(countValues)), 0, 0, 1000).messages
# => []

Answer 1

After debugging and reading docs, I noticed the following sentence in bufferedWithTime documentation: [scheduler=Rx.Scheduler.timeout] (Scheduler): Scheduler to run buffer timers on. If not specified, the timeout scheduler is used.
I had thought that when creating observable from TestScheduler, it will use that scheduler for all it's methods but the scheduler has to be passed in explicitly. So below is the correct solution:
print = (event) -> console.log "Event: ", event
Rx = require 'rx'
onNext = Rx.ReactiveTest.onNext
TEST_EVENT_A = { messageName: 'test_event_a', namespace: 'test' }
events = [onNext(50, TEST_EVENT_A), onNext(100, TEST_EVENT_A)]
scheduler = new Rx.TestScheduler
stream = scheduler.createHotObservable events
excludeEmpty = (event) -> console.log "Filtering...", event; event.length > 0
countValues = (event) -> console.log "Counting...", event; event.length
# Notice the 2nd argument to bufferWithTime
res = scheduler.startWithTiming((=> stream.bufferWithTime(100, scheduler).filter(excludeEmpty).map(countValues)), 0, 0, 1500).messages
# => res[0].value.value == 2