Inject LinkOpener safari factory for testing

Author: weiran

Shared/Sources/Shared/Services/LinkOpener.swift

@@ -27,6 +27,10 @@ public enum LinkOpener {
         presenter.present(safariVC, animated: true)
     }
 
+    private static var safariControllerFactory: (URL, SFSafariViewController.Configuration) -> SFSafariViewController = { url, configuration in
+        SFSafariViewController(url: url, configuration: configuration)
+    }
+
     public static func openURL(_ url: URL, with _: Post? = nil) {
         // Determine user preference for opening links via injected settings use case
         let settings = settingsProvider()
@@ -40,7 +44,7 @@ public enum LinkOpener {
                 let config = SFSafariViewController.Configuration()
                 config.entersReaderIfAvailable = settings.safariReaderMode
 
-                let safariVC = SFSafariViewController(url: url, configuration: config)
+                let safariVC = safariControllerFactory(url, config)
                 safariPresenter(presenter, safariVC)
             } else {
                 // Fallback if we cannot present in-app browser
@@ -87,18 +91,23 @@ public enum LinkOpener {
         settings: (() -> any SettingsUseCase)? = nil,
         openURL: ((URL) -> Void)? = nil,
         presenter: (() -> UIViewController?)? = nil,
-        presentSafari: ((UIViewController, SFSafariViewController) -> Void)? = nil
+        presentSafari: ((UIViewController, SFSafariViewController) -> Void)? = nil,
+        safariControllerFactory: ((URL, SFSafariViewController.Configuration) -> SFSafariViewController)? = nil
     ) {
         if let settings { settingsProvider = settings }
         if let openURL { systemOpener = openURL }
         if let presenter { presenterProvider = presenter }
         if let presentSafari { safariPresenter = presentSafari }
+        if let safariControllerFactory { self.safariControllerFactory = safariControllerFactory }
     }
 
     static func resetEnvironment() {
         settingsProvider = { DependencyContainer.shared.getSettingsUseCase() }
         systemOpener = { url in UIApplication.shared.open(url) }
         presenterProvider = { findPresenter() }
         safariPresenter = { presenter, safariVC in presenter.present(safariVC, animated: true) }
+        safariControllerFactory = { url, configuration in
+            SFSafariViewController(url: url, configuration: configuration)
+        }
     }
 }

Shared/Tests/SharedTests/LinkOpenerTests.swift

@@ -38,27 +38,46 @@ struct LinkOpenerTests {
     func presentsSafariViewController() {
         let settings = StubSettingsUseCase(safariReaderMode: true, openInDefaultBrowser: false)
         var capturedPresented: (UIViewController, SFSafariViewController)?
+        var capturedFactoryInput: (URL, SFSafariViewController.Configuration)?
+        var stubSafari: StubSafariViewController?
 
         LinkOpener.setEnvironmentForTesting(
             settings: { settings },
             openURL: { _ in Issue.record("Should not open system browser when presenter exists") },
             presenter: { StubPresenter() },
             presentSafari: { presenter, safari in
                 capturedPresented = (presenter, safari)
+            },
+            safariControllerFactory: { url, configuration in
+                capturedFactoryInput = (url, configuration)
+                let controller = StubSafariViewController(url: url, configuration: configuration)
+                stubSafari = controller
+                return controller
             }
         )
 
+        defer { LinkOpener.resetEnvironment() }
+
         let url = URL(string: "https://news.ycombinator.com")!
         LinkOpener.openURL(url)
 
-        guard let (_, safariController) = capturedPresented else {
+        guard let factoryInput = capturedFactoryInput else {
+            Issue.record("Expected safariControllerFactory to be invoked")
+            return
+        }
+
+        #expect(factoryInput.0 == url)
+        #expect(factoryInput.1.entersReaderIfAvailable)
+
+        guard let (presenter, safariController) = capturedPresented else {
             Issue.record("Expected Safari to be presented")
             return
         }
 
-        #expect(safariController.initialURL == url)
-        #expect(safariController.resolvedConfiguration.entersReaderIfAvailable)
-        LinkOpener.resetEnvironment()
+        #expect(presenter is StubPresenter)
+        #expect(safariController === stubSafari)
+        #expect(stubSafari?.capturedURL == url)
+        #expect(stubSafari?.capturedConfiguration.entersReaderIfAvailable == true)
     }
 
     @MainActor
@@ -121,15 +140,18 @@ private final class StubSettingsUseCase: SettingsUseCase, @unchecked Sendable {
 
 private final class StubPresenter: UIViewController {}
 
-private extension SFSafariViewController {
-    var initialURL: URL {
-        // SFSafariViewController exposes the initial URL through private API, but we can rely on the
-        // view controller's `value(forKey:)` for testing purposes in the test bundle.
-        value(forKey: "URL") as? URL ?? URL(string: "about:blank")!
+private final class StubSafariViewController: SFSafariViewController {
+    let capturedURL: URL
+    let capturedConfiguration: SFSafariViewController.Configuration
+
+    override init(url: URL, configuration: SFSafariViewController.Configuration) {
+        capturedURL = url
+        capturedConfiguration = configuration
+        super.init(url: url, configuration: configuration)
     }
 
-    var resolvedConfiguration: SFSafariViewController.Configuration {
-        (value(forKey: "configuration") as? SFSafariViewController.Configuration)
-            ?? SFSafariViewController.Configuration()
+    @available(*, unavailable)
+    override required init(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
     }
 }