Allow .introspectNavigationController() on NavigationView directly

CHANGELOG.md

@@ -1,6 +1,10 @@
 Changelog
 =========
 
+## master
+
+ - Allow `.introspectNavigationController()` on NavigationView directly.
+
 ## [0.0.4]
 
  - Fix a bug in 0.0.4 that would not allow customization of root elements.

Introspect/Introspect.swift

@@ -20,6 +20,23 @@ public enum Introspect {
         return nil
     }
     
+    /// Finds a child view controller of the specified type.
+    /// This method will recursively look for this child.
+    /// Returns nil if it can't find a view of the specified type.
+    public static func findChild<AnyViewControllerType: UIViewController>(
+        ofType type: AnyViewControllerType.Type,
+        in root: UIViewController
+    ) -> AnyViewControllerType? {
+        for child in root.children {
+            if let typed = child as? AnyViewControllerType {
+                return typed
+            } else if let typed = findChild(ofType: type, in: child) {
+                return typed
+            }
+        }
+        return nil
+    }
+    
     /// Finds a previous sibling that contains a view of the specified type.
     /// This method inspects siblings recursively.
     /// Returns nil if no sibling contains the specified type.
@@ -44,6 +61,30 @@ public enum Introspect {
         return nil
     }
     
+    /// Finds a previous sibling that contains a view controller of the specified type.
+    /// This method inspects siblings recursively.
+    /// Returns nil if no sibling contains the specified type.
+    public static func previousSibling<AnyViewControllerType: UIViewController>(
+        containing type: AnyViewControllerType.Type,
+        from entry: UIViewController
+    ) -> AnyViewControllerType? {
+        
+        guard let parent = entry.parent,
+            let entryIndex = parent.children.firstIndex(of: entry),
+            entryIndex > 0
+        else {
+            return nil
+        }
+        
+        for child in parent.children[0..<entryIndex].reversed() {
+            if let typed = findChild(ofType: type, in: child) {
+                return typed
+            }
+        }
+        
+        return nil
+    }
+    
     /// Finds a next sibling that contains a view of the specified type.
     /// This method inspects siblings recursively.
     /// Returns nil if no sibling contains the specified type.
@@ -279,7 +320,16 @@ extension View {
     /// Finds a `UINavigationController` from any view embedded in a `SwiftUI.NavigationView`.
     public func introspectNavigationController(customize: @escaping (UINavigationController) -> ()) -> some View {
         return inject(IntrospectionViewController(
-            selector: { $0.navigationController },
+            selector: { introspectionViewController in
+                
+                // Search in ancestors
+                if let navigationController = introspectionViewController.navigationController {
+                    return navigationController
+                }
+                
+                // Search in siblings
+                return Introspect.previousSibling(containing: UINavigationController.self, from: introspectionViewController)
+            },
             customize: customize
         ))
     }

IntrospectTests/IntrospectTests.swift

@@ -17,6 +17,20 @@ private struct NavigationTestView: View {
     }
 }
 
+private struct NavigationRootTestView: View {
+    let spy: () -> Void
+    var body: some View {
+        NavigationView {
+            VStack {
+                EmptyView()
+            }
+        }
+        .introspectNavigationController { navigationController in
+            self.spy()
+        }
+    }
+}
+
 private struct ListTestView: View {
     
     let spy1: () -> Void
@@ -128,6 +142,16 @@ class IntrospectTests: XCTestCase {
         wait(for: [expectation], timeout: 1)
     }
     
+    func testRootNavigation() {
+        
+        let expectation = XCTestExpectation()
+        let view = NavigationRootTestView(spy: {
+            expectation.fulfill()
+        })
+        TestUtils.present(view: view)
+        wait(for: [expectation], timeout: 1)
+    }
+    
     func testList() {
         
         let expectation1 = XCTestExpectation()

README.md

@@ -51,7 +51,7 @@ SwiftUI | UIKit | Introspect | Target
 --- | --- | --- | ---
 List | UITableView | `.introspectTableView()` | List, or List child
 ScrollView | UIScrollView | `.introspectScrollView()` | ScrollView, or ScrollView child
-NavigationView | UINavigationController | `.introspectNavigationController()` | **NavigationView child**
+NavigationView | UINavigationController | `.introspectNavigationController()` | NavigationView, or NavigationView child
 TabbedView | UITabBarController | `.introspectTabBarController()` | **TabbedView child**
 TextField | UITextField | `.introspectTextField()` | TextField
 Toggle | UISwitch | `.introspectSwitch()` | Toggle