Improve lifecycle

HammerTests.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |spec|
   spec.name          = "HammerTests"
-  spec.version       = "0.15.0"
-  spec.summary       = "iOS touch and keyboard syntheis library for unit tests."
+  spec.version       = "0.16.0"
+  spec.summary       = "iOS touch and keyboard synthesis library for unit tests."
   spec.description   = "Hammer is a touch and keyboard synthesis library for emulating user interaction events. It enables new ways of triggering UI actions in unit tests, replicating a real world environment as much as possible."
   spec.homepage      = "https://github.com/lyft/Hammer"
   spec.screenshots   = "https://user-images.githubusercontent.com/585835/116217617-ab410080-a6fe-11eb-9de1-3d42f7dd6037.gif"

Sources/Hammer/EventGenerator/EventGenerator.swift

@@ -22,12 +22,11 @@ public final class EventGenerator {
     public let window: UIWindow
 
     /// The view that was used to create the event generator
-    public private(set) var mainView: UIView
+    public let mainView: UIView
 
     var activeTouches = TouchStorage()
     var debugWindow = DebugVisualizerWindow()
     var eventCallbacks = [UInt32: CompletionHandler]()
-    private var isUsingCustomWindow: Bool = false
 
     /// The default sender id for all events.
     ///
@@ -42,18 +41,25 @@ public final class EventGenerator {
 
     /// Initialize an event generator for a specified UIWindow.
     ///
-    /// - parameter window: The window to receive events.
-    public init(window: UIWindow) throws {
+    /// - parameter window:   The window to receive events.
+    /// - parameter mainView: The view that was used to create the event generator
+    private init(window: UIWindow, mainView: UIView) throws {
         self.window = window
+        self.mainView = mainView
         self.window.layoutIfNeeded()
         self.debugWindow.frame = self.window.frame
-        self.mainView = window
 
         UIApplication.swizzle()
         UIApplication.registerForHIDEvents(ObjectIdentifier(self)) { [weak self] event in
             self?.markerEventReceived(event)
         }
+    }
 
+    /// Initialize an event generator for a specified UIWindow.
+    ///
+    /// - parameter window: The window to receive events.
+    public convenience init(window: UIWindow) throws {
+        try self.init(window: window, mainView: window)
         try self.waitUntilWindowIsReady()
     }
 
@@ -64,20 +70,15 @@ public final class EventGenerator {
     ///
     /// - parameter viewController: The viewController to receive events.
     public convenience init(viewController: UIViewController) throws {
-        let window = viewController.view.window ?? UIWindow(wrapping: viewController)
-
-        if #available(iOS 13.0, *) {
-            window.backgroundColor = .systemBackground
+        if let window = viewController.view.window  {
+            try self.init(window: window, mainView: viewController.view)
         } else {
-            window.backgroundColor = .white
+            let window = HammerWindow()
+            window.presentContained(viewController)
+            try self.init(window: window, mainView: viewController.view)
         }
 
-        window.makeKeyAndVisible()
-        window.layoutIfNeeded()
-
-        try self.init(window: window)
-        self.isUsingCustomWindow = true
-        self.mainView = viewController.view
+        try self.waitUntilWindowIsReady()
     }
 
     /// Initialize an event generator for a specified UIView.
@@ -88,25 +89,22 @@ public final class EventGenerator {
     /// - parameter alignment: The wrapping alignment to use.
     public convenience init(view: UIView, alignment: WrappingAlignment = .center) throws {
         if let window = view.window {
-            try self.init(window: window)
+            try self.init(window: window, mainView: view)
         } else {
-            try self.init(viewController: UIViewController(wrapping: view.topLevelView, alignment: alignment))
+            let viewController = UIViewController(wrapping: view.topLevelView, alignment: alignment)
+            let window = HammerWindow()
+            window.presentContained(viewController)
+            try self.init(window: window, mainView: view)
         }
 
-        self.mainView = view
+        try self.waitUntilWindowIsReady()
     }
 
     deinit {
         UIApplication.unregisterForHIDEvents(ObjectIdentifier(self))
-        if self.isUsingCustomWindow {
-            self.window.isHidden = true
-            self.window.rootViewController = nil
-            self.debugWindow.isHidden = true
-            self.debugWindow.rootViewController = nil
-            if #available(iOS 13.0, *) {
-                self.window.windowScene = nil
-                self.debugWindow.windowScene = nil
-            }
+        self.debugWindow.removeFromScene()
+        if let window = self.window as? HammerWindow {
+            window.dismissContained()
         }
     }
 

Sources/Hammer/Utilties/HammerWindow.swift

@@ -0,0 +1,129 @@
+import UIKit
+
+// Custom Window to have proper simulation of presentation and dismissal lifecycle events
+final class HammerWindow: UIWindow {
+    private let hammerViewController = HammerViewController()
+
+    override var safeAreaInsets: UIEdgeInsets {
+        return .zero
+    }
+
+    init() {
+        super.init(frame: UIScreen.main.bounds)
+        self.rootViewController = self.hammerViewController
+
+        if #available(iOS 13.0, *) {
+            self.backgroundColor = .systemBackground
+        } else {
+            self.backgroundColor = .white
+        }
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    func presentContained(_ viewController: UIViewController) {
+        self.makeVisibleAndKey()
+        self.hammerViewController.presentContained(viewController)
+    }
+
+    func dismissContained() {
+        self.hammerViewController.dismissContained()
+        self.removeFromScene(removeViewController: false)
+    }
+}
+
+private final class HammerViewController: UIViewController {
+    private let containerView = UIView()
+
+    override var shouldAutomaticallyForwardAppearanceMethods: Bool { false }
+    override var prefersStatusBarHidden: Bool { true }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        self.view.backgroundColor = .clear
+        self.containerView.translatesAutoresizingMaskIntoConstraints = false
+        self.view.addSubview(self.containerView)
+
+        // We only activate the top and leading constraints to allow the content to size itself.
+        NSLayoutConstraint.activate([
+            self.containerView.topAnchor.constraint(equalTo: self.view.topAnchor),
+            self.containerView.bottomAnchor.constraint(equalTo: self.view.bottomAnchor),
+            self.containerView.leadingAnchor.constraint(equalTo: self.view.leadingAnchor),
+            self.containerView.trailingAnchor.constraint(equalTo: self.view.trailingAnchor),
+        ])
+    }
+
+    func presentContained(_ viewController: UIViewController) {
+        viewController.beginAppearanceTransition(true, animated: false)
+        self.addChild(viewController)
+
+        viewController.view.translatesAutoresizingMaskIntoConstraints = false
+        self.containerView.addSubview(viewController.view)
+        NSLayoutConstraint.activate([
+            viewController.view.topAnchor.constraint(equalTo: self.containerView.topAnchor),
+            viewController.view.bottomAnchor.constraint(equalTo: self.containerView.bottomAnchor),
+            viewController.view.leadingAnchor.constraint(equalTo: self.containerView.leadingAnchor),
+            viewController.view.trailingAnchor.constraint(equalTo: self.containerView.trailingAnchor),
+        ])
+
+        viewController.didMove(toParent: self)
+        viewController.endAppearanceTransition()
+        self.view.layoutIfNeeded()
+    }
+
+    func dismissContained() {
+        for viewController in self.children {
+            viewController.beginAppearanceTransition(false, animated: false)
+            viewController.willMove(toParent: nil)
+            viewController.view.removeFromSuperview()
+            viewController.removeFromParent()
+            viewController.endAppearanceTransition()
+        }
+    }
+}
+
+extension UIWindow {
+    func makeVisibleAndKey(file: StaticString = #file, line: UInt = #line) {
+        self.addToMainSceneIfNeeded(file: file, line: line)
+        self.makeKeyAndVisible()
+    }
+
+    func addToMainSceneIfNeeded(file: StaticString = #file, line: UInt = #line) {
+        guard #available(iOS 13.0, *) else {
+            return
+        }
+
+        guard self.windowScene == nil else {
+            return
+        }
+
+        if let mainScene = UIScene.mainOrFirstConnectedScene {
+            self.windowScene = mainScene
+        } else {
+            assertionFailure("Unable to find main scene", file: file, line: line)
+        }
+    }
+
+    func removeFromScene(removeViewController: Bool = true) {
+        self.isHidden = true
+
+        if #available(iOS 13.0, *) {
+            self.windowScene = nil
+        }
+
+        if removeViewController {
+            self.rootViewController = nil
+        }
+    }
+}
+
+@available(iOS 13.0, *)
+private extension UIScene {
+    static var mainOrFirstConnectedScene: UIWindowScene? {
+        let scenes = UIApplication.shared.connectedScenes.compactMap { $0 as? UIWindowScene }
+        return scenes.first { $0.screen == UIScreen.main } ?? scenes.first
+    }
+}

Sources/Hammer/Utilties/UIKit+Extensions.swift

@@ -43,17 +43,6 @@ extension UIDevice {
     }
 }
 
-extension UIWindow {
-    convenience init(wrapping viewController: UIViewController) {
-        self.init(frame: UIScreen.main.bounds)
-        if #available(iOS 13.0, *), self.windowScene == nil {
-            self.windowScene = UIApplication.shared.connectedScenes
-                .compactMap { $0 as? UIWindowScene }.first
-        }
-        self.rootViewController = viewController
-    }
-}
-
 extension UIViewController {
     convenience init(wrapping view: UIView, alignment: EventGenerator.WrappingAlignment) {
         self.init(nibName: nil, bundle: nil)

Tests/HammerTests/KeyboardTests.swift

@@ -187,8 +187,11 @@ final class KeyboardTests: XCTestCase {
             view.centerXAnchor.constraint(equalTo: viewController.view.centerXAnchor),
         ])
 
-        let window = UIWindow(wrapping: viewController)
+        let window = UIWindow(frame: UIScreen.main.bounds)
+        window.rootViewController = viewController
+        window.addToMainSceneIfNeeded()
         window.isHidden = false
+        defer { window.removeFromScene() }
 
         let eventGenerator = try EventGenerator(window: window)
         try eventGenerator.waitUntilHittable(timeout: 1)