public void ChangesTriggerPropertyChangedEvent()
            {
                var vm = new ScreenControllerViewModel();

                vm.ShouldNotifyOn(x => x.CurrentScreen).When(x => x.CurrentScreen = "New Value");
            }
            public void SetterSetsAndGetterGets()
            {
                var vm = new ScreenControllerViewModel { CurrentScreen = "A Test String" };

                Assert.Equal("A Test String", vm.CurrentScreen);
            }
            public void InitsTheCurrentScreenToStartScreen()
            {
                var vm = new ScreenControllerViewModel();

                Assert.IsType<StartScreenViewModel>(vm.CurrentScreen);
            }