     @set.add(itemsToAdd...)
 
     @set.on 'itemsWereAdded', addSpy = createSpy()
-    @set.on 'itemsWereRemoved', 'change', listen = createSpy()
+    @set.on 'itemsWereRemoved', listen = createSpy()
 
     change = @set.addAndRemove([], [o1, o2])
 

    ok @set.has(o1)
    ok @set.has(o2)
    ok @set.has(o3)
    equal listen.callCount, 2
    ok !removeSpy.called

  test "addAndRemove only removes item to the set if no items to add are passed", ->

    equal @set.length, 1

  test "addAndRemove only adds item to the set if no items to remove are passed", ->
    @set.on 'itemsWereAdded', listen = createSpy()
    @set.on 'itemsWereRemoved', removeSpy = createSpy()

    itemsToAdd = [o1 = {}, o2 = {}, o3 = {}]
