     expectStreamEvents(
       -> series(2, [1,2,3]).toProperty()
         .delay(t(2)).changes().takeUntil(Bacon.later(t(5)))
-      [1], {unstable:true})
+      [1], unstable)
   describe "does not delay initial value", ->
     expectPropertyEvents(
       -> series(3, [1]).toProperty(0).delay(1).takeUntil(Bacon.later(t(2)))

  describe "Works also when f returns a Property instead of an EventStream", ->
    expectStreamEvents(
      -> series(1, [1,2]).flatMap(Bacon.constant)
      [1,2], {unstable:true})
  describe "Works also when f returns a constant value instead of an EventStream", ->
    expectStreamEvents(
      -> series(1, [1,2]).flatMap((x) -> x)
      [1,2], {unstable:true})
  describe "Accepts a constant EventStream/Property as an alternative to a function", ->
    expectStreamEvents(
      -> Bacon.once("asdf").flatMap(Bacon.constant("bacon"))

      -> 
        p = series(5, [1, 2]).toProperty()
        p.sampledBy(series(3, [0, 0, 0, 0]))
      [1, 1, 2], unstable)
    expectPropertyEvents(
      -> 
        p = series(5, [1, 2]).toProperty()
        p.sampledBy(series(3, [0, 0, 0, 0]).toProperty())
      [1, 1, 2], unstable)
  describe "works with stream of functions", ->
    f = ->
    expectStreamEvents(
