Add .introspectSplitViewController() on iOS (#89)

.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "self:">
+   </FileRef>
+</Workspace>

CHANGELOG.md

@@ -3,6 +3,7 @@ Changelog
 
 ## master
 
+- Added `.introspectSplitViewController()` on iOS
 - Fixed iPad tests
 - Added iPad to CI
 - Added `.introspectColorWell()` on iOS and macOS

Introspect/Introspect.swift

@@ -48,7 +48,7 @@ public enum Introspect {
                 return typed
             }
         }
-        return nil
+        return root as? AnyViewControllerType
     }
     
     /// Finds a subview of the specified type.

Introspect/ViewExtensions.swift

@@ -45,6 +45,23 @@ extension View {
         ))
     }
     
+    /// Finds a `UISplitViewController` from  a `SwiftUI.NavigationView` with style `DoubleColumnNavigationViewStyle`.
+    public func introspectSplitViewController(customize: @escaping (UISplitViewController) -> ()) -> some View {
+            return inject(UIKitIntrospectionViewController(
+                selector: { introspectionViewController in
+                    
+                    // Search in ancestors
+                    if let splitViewController = introspectionViewController.splitViewController {
+                        return splitViewController
+                    }
+                    
+                    // Search in siblings
+                    return Introspect.previousSibling(containing: UISplitViewController.self, from: introspectionViewController)
+                },
+                customize: customize
+            ))
+        }
+    
     /// Finds the containing `UIViewController` of a SwiftUI view.
     public func introspectViewController(customize: @escaping (UIViewController) -> ()) -> some View {
         return inject(UIKitIntrospectionViewController(

IntrospectTests/UIKitTests.swift

@@ -49,6 +49,22 @@ private struct NavigationTestView: View {
     }
 }
 
+@available(iOS 13.0, tvOS 13.0, macOS 10.15.0, *)
+private struct SplitNavigationTestView: View {
+    let spy: () -> Void
+    var body: some View {
+        NavigationView {
+            VStack {
+                EmptyView()
+            }
+        }
+        .navigationViewStyle(DoubleColumnNavigationViewStyle())
+        .introspectSplitViewController { navigationController in
+            self.spy()
+        }
+    }
+}
+
 @available(iOS 13.0, tvOS 13.0, macOS 10.15.0, *)
 private struct ViewControllerTestView: View {
     let spy: () -> Void
@@ -477,6 +493,16 @@ class UIKitTests: XCTestCase {
     }
     
     #if os(iOS)
+    func testSplitNavigation() {
+        
+        let expectation = XCTestExpectation()
+        let view = SplitNavigationTestView(spy: {
+            expectation.fulfill()
+        })
+        TestUtils.present(view: view)
+        wait(for: [expectation], timeout: TestUtils.Constants.timeout)
+    }
+    
     func testRootNavigation() {
         
         let expectation = XCTestExpectation()