describe('merge', function()
  it('produces values from the first observable if it is the only argument', function()
    local observable = Rx.Observable.fromRange(5):merge()
    expect(observable).to.produce(1, 2, 3, 4, 5)
  end)

  it('unsubscribes from all input observables', function()
    local observableA = Rx.Observable.create(function(observer)
      return
    end)

    local unsubscribeB = spy()
    local subscriptionB = Rx.Subscription.create(unsubscribeB)
    local observableB = Rx.Observable.create(function(observer)
      return subscriptionB
    end)

    local subscription = observableA:merge(observableB):subscribe()
    subscription:unsubscribe()
    expect(#unsubscribeB).to.equal(1)
  end)

  it('produces values from all input observables, in order', function()
    local observableA = Rx.Subject.create()
    local observableB = Rx.Subject.create()
    local merged = observableA:merge(observableB)
    local onNext, onError, onCompleted = observableSpy(merged)
    observableA:onNext('a')
    observableB:onNext('b')
    observableB:onNext('b')
    observableA:onNext('a')
    observableA:onCompleted()
    observableB:onCompleted()
    expect(onNext).to.equal({{'a'}, {'b'}, {'b'}, {'a'}})
  end)

  it('completes when all source observables complete', function()
    local observableA = Rx.Subject.create()
    local observableB = Rx.Subject.create()
    local complete = spy()
    Rx.Observable.merge(observableA, observableB):subscribe(nil, nil, complete)

    expect(#complete).to.equal(0)
    observableA:onNext(1)
    expect(#complete).to.equal(0)
    observableB:onNext(2)
    expect(#complete).to.equal(0)
    observableB:onCompleted()
    expect(#complete).to.equal(0)
    observableA:onCompleted()
    expect(#complete).to.equal(1)
  end)
end)