uisegmentedcontrol_example.rb

class FeedScreen < PM::Screen
  def on_load
    @control ||= begin 
      c = UISegmentedControl.plain ["all", "following"]
      c.selectedSegmentIndex = 0
      c.accessibilityLabel = "nav_control"
      c.on :change.uicontrolevent do
        switch_screens
      end
      c 
    end

    self.navigationItem.titleView = @control
  end

  def switch_screens
    # switch screens
  end
end

# testing with the actual feed screen fails
describe "Feed Screen" do
  tests FeedScreen

  def controller
    @controller ||= FeedScreen.new nav_bar: true
  end

  it "should call the :switch_screens method when clicking a control button" do
    # fails
    controller.mock!(:switch_screens)
    tap controller.navigationItem.titleView :at => :right
  end
end

# targeting the feed screens navigation controller successfully runs the specs
describe "Feed Screen" do
  tests PM::NavigationController

  def controller
    @controller ||= FeedScreen.new nav_bar: true
    @controller.navigationController
  end

  it "should call the :switch_screens method when clicking a control button" do
    controller.mock!(:switch_screens)
    tap controller.navigationBar.topItem, :at => :right
  end
end