spec.swift

override func spec() 
{
  var subject: UIViewController!, viewModel: ViewModel!
  beforeEach { (subject, viewModel) = self.newSubject }

  context("once the view has loaded") {
    beforeEach { subject.loadViewIfNeeded() }

    describe("events sent to view model") {
      context("when selection changes") {
        beforeEach { subject.pickerView.selectedIndex = 1 }

        it("sets view model selected index") {
          expext(viewModel.selectedIndex).to(equal(1))
        }
      }

      context("when the button is tapped") {
        beforeEach { subject.button.tap() }

        it("calls ViewModel.buttonTapHandler") {
          expect(viewModel.buttonTapHandlerCalled).to(beTrue())
        }
      }
    }

    describe("updates recieved from view model") {
      context("when phone number changes") {
        beforeEach { viewModel.phoneNumber.value = "(555) 867-5309" }

        it("updates the label") {
          expect(subject.phoneNumberLabel.text).toEventually(equal("(555) 867-5309"))
        }
      }

      // #1
      context("when the location changes") {
        beforeEach { viewModel.location.value = Location.NYC }

        it("updates latitude label") {
          expect(subject.latituteLabel.text).to(equal(Location.NYC.latitude))
        }

        it("updates longitude label") {
          expect(subject.longitudeLabel.text).to(equal(Location.NYC.longitude))
        }
      }
      
      // #2
      it("binds location to appropriate labels") {
        viewModel.location.value = Location.NYC
        expect(subject.latituteLabel.text).to(equal(Location.NYC.latitude))
        expect(subject.longitudeLabel.text).to(equal(Location.NYC.longitude))
      }
    }
  }
}