[NT-876] Pop ProjectPamphlet to root after project is backed

Kickstarter-iOS/Views/Controllers/ProjectPamphletViewController.swift

@@ -164,6 +164,12 @@ public final class ProjectPamphletViewController: UIViewController, MessageBanne
           self?.messageBannerViewController?.showBanner(with: .success, message: message)
         })
       }
+
+    self.viewModel.outputs.popToRootViewController
+      .observeForControllerAction()
+      .observeValues { [weak self] in
+        self?.navigationController?.popToRootViewController(animated: false)
+      }
   }
 
   public override func willTransition(

Library/ViewModels/ProjectPamphletViewModel.swift

@@ -50,6 +50,9 @@ public protocol ProjectPamphletViewModelOutputs {
   /// Emits a project and refTag to be used to navigate to the reward selection screen.
   var goToRewards: Signal<(Project, RefTag?), Never> { get }
 
+  /// Emits when the navigation stack should be popped to the root view controller.
+  var popToRootViewController: Signal<(), Never> { get }
+
   /// Emits two booleans that determine if the navigation bar should be hidden, and if it should be animated.
   var setNavigationBarHiddenAnimated: Signal<(Bool, Bool), Never> { get }
 
@@ -70,6 +73,8 @@ public final class ProjectPamphletViewModel: ProjectPamphletViewModelType, Proje
   public init() {
     let isLoading = MutableProperty(false)
 
+    self.popToRootViewController = self.didBackProjectProperty.signal.ignoreValues()
+
     let freshProjectAndRefTagEvent = self.configDataProperty.signal.skipNil()
       .takePairWhen(Signal.merge(
         self.viewDidLoadProperty.signal.mapConst(true),
@@ -263,6 +268,7 @@ public final class ProjectPamphletViewModel: ProjectPamphletViewModelType, Proje
   public let dismissManagePledgeAndShowMessageBannerWithMessage: Signal<String, Never>
   public let goToManagePledge: Signal<Project, Never>
   public let goToRewards: Signal<(Project, RefTag?), Never>
+  public let popToRootViewController: Signal<(), Never>
   public let setNavigationBarHiddenAnimated: Signal<(Bool, Bool), Never>
   public let setNeedsStatusBarAppearanceUpdate: Signal<(), Never>
   public let topLayoutConstraintConstant: Signal<CGFloat, Never>

Library/ViewModels/ProjectPamphletViewModelTests.swift

@@ -23,6 +23,7 @@ final class ProjectPamphletViewModelTests: TestCase {
   private let goToManageViewPledge = TestObserver<Project, Never>()
   private let goToRewardsProject = TestObserver<Project, Never>()
   private let goToRewardsRefTag = TestObserver<RefTag?, Never>()
+  private let popToRootViewController = TestObserver<(), Never>()
   private let setNavigationBarHidden = TestObserver<Bool, Never>()
   private let setNavigationBarAnimated = TestObserver<Bool, Never>()
   private let setNeedsStatusBarAppearanceUpdate = TestObserver<(), Never>()
@@ -64,6 +65,7 @@ final class ProjectPamphletViewModelTests: TestCase {
     self.vm.outputs.goToManagePledge.observe(self.goToManageViewPledge.observer)
     self.vm.outputs.goToRewards.map(first).observe(self.goToRewardsProject.observer)
     self.vm.outputs.goToRewards.map(second).observe(self.goToRewardsRefTag.observer)
+    self.vm.outputs.popToRootViewController.observe(self.popToRootViewController.observer)
     self.vm.outputs.setNavigationBarHiddenAnimated.map(first)
       .observe(self.setNavigationBarHidden.observer)
     self.vm.outputs.setNavigationBarHiddenAnimated.map(second)
@@ -1011,6 +1013,17 @@ final class ProjectPamphletViewModelTests: TestCase {
     }
   }
 
+  func testPopToRootViewController() {
+    self.vm.inputs.configureWith(projectOrParam: .left(.template), refTag: nil)
+    self.vm.inputs.viewDidLoad()
+
+    self.popToRootViewController.assertDidNotEmitValue()
+
+    self.vm.inputs.didBackProject()
+
+    self.popToRootViewController.assertValueCount(1)
+  }
+
   // MARK: - Functions
 
   private func configureInitialState(_ projectOrParam: Either<Project, Param>) {