Create AppKitExtras tests. Add it to test plan. Add parser tests to test plan.

AppKitExtras/Tests/AppKitExtrasTests/AppKitExtrasTests.swift

@@ -1,12 +0,0 @@
-import XCTest
-@testable import AppKitExtras
-
-final class AppKitExtrasTests: XCTestCase {
-    func testExample() throws {
-        // XCTest Documentation
-        // https://developer.apple.com/documentation/xctest
-
-        // Defining Test Cases and Test Methods
-        // https://developer.apple.com/documentation/xctest/defining_test_cases_and_test_methods
-    }
-}

AppKitExtras/Tests/AppKitExtrasTests/NSMenuExtensionsTests.swift

@@ -0,0 +1,65 @@
+//
+//  NSMenuExtensionsTests.swift
+//  
+//
+//  Created by Brent Simmons on 5/18/24.
+//
+
+#if os(macOS)
+
+import AppKit
+import XCTest
+import AppKitExtras
+
+final class NSMenuExtensionsTests: XCTestCase {
+
+	// MARK: - Test addSeparatorIfNeeded
+
+	func testAddSeparatorIfNeeded_NoSeparator() {
+
+		let menu = NSMenu(title: "Test")
+		menu.addItem(menuItemForTesting())
+		menu.addItem(menuItemForTesting())
+		menu.addSeparatorIfNeeded()
+
+		XCTAssertTrue(menu.items.last!.isSeparatorItem)
+	}
+
+	func testAddSeparatorIfNeeded_EmptyMenu() {
+
+		let menu = NSMenu(title: "Test")
+		menu.addSeparatorIfNeeded()
+
+		// A separator should not be added to a menu with 0 items,
+		// since a menu should never start with a separator item.
+		XCTAssertEqual(menu.items.count, 0)
+	}
+
+	func testAddSeparatorIfNeeded_HasSeparator() {
+
+		let menu = NSMenu(title: "Test")
+		menu.addItem(menuItemForTesting())
+		menu.addItem(menuItemForTesting())
+		menu.addItem(.separator())
+
+		let menuItemsCount = menu.items.count
+
+		XCTAssertTrue(menu.items.last!.isSeparatorItem)
+
+		// Should not get added — last item is already separator
+		menu.addSeparatorIfNeeded()
+		// Make sure last item is still separator
+		XCTAssertTrue(menu.items.last!.isSeparatorItem)
+		// Count should be same as before calling `addSeparatorIfNeeded()`
+		XCTAssertEqual(menu.items.count, menuItemsCount)
+	}
+}
+
+private extension NSMenuExtensionsTests {
+
+	private func menuItemForTesting(_ title: String = "Test NSMenuItem") -> NSMenuItem {
+		NSMenuItem(title: title, action: nil, keyEquivalent: "")
+	}
+}
+
+#endif