Add introspection for `NSTabView` (#84)

Add introspection for `NSTabView`

CHANGELOG.md

@@ -3,6 +3,8 @@ Changelog
 
 ## master
 
+- Added `.introspectTabView()` on macOS
+
 ## [0.1.3]
 
 - Added `introspectTableViewCell`

Introspect/ViewExtensions.swift

@@ -193,5 +193,10 @@ extension View {
     public func introspectSegmentedControl(customize: @escaping (NSSegmentedControl) -> ()) -> some View {
         return introspect(selector: TargetViewSelector.siblingContaining, customize: customize)
     }
+    
+    /// Finds a `NSTabView` from a `SwiftUI.TabView`
+    public func introspectTabView(customize: @escaping (NSTabView) -> ()) -> some View {
+        return introspect(selector: TargetViewSelector.siblingContaining, customize: customize)
+    }
 }
 #endif

IntrospectTests/AppKitTests.swift

@@ -183,6 +183,26 @@ private struct SegmentedControlTestView: View {
     }
 }
 
+@available(macOS 10.15.0, *)
+private struct TabViewTestView: View {
+    let spy: () -> Void
+    var body: some View {
+        TabView {
+            Text("Contents")
+                .tabItem {
+                    Text("Tab 1")
+                }
+            Text("Contents")
+                .tabItem {
+                    Text("Tab 2")
+                }
+        }
+        .introspectTabView { tabView in
+            self.spy()
+        }
+    }
+}
+
 @available(macOS 10.15.0, *)
 class AppKitTests: XCTestCase {
     
@@ -316,5 +336,15 @@ class AppKitTests: XCTestCase {
         TestUtils.present(view: view)
         wait(for: [expectation], timeout: TestUtils.Constants.timeout)
     }
+    
+    func testTabView() {
+        
+        let expectation = XCTestExpectation()
+        let view = TabViewTestView(spy: {
+            expectation.fulfill()
+        })
+        TestUtils.present(view: view)
+        wait(for: [expectation], timeout: TestUtils.Constants.timeout)
+    }
 }
 #endif