// 1
func testHasAddBarButton() {
    let barButtonItem = controller.navigationItem.rightBarButtonItem
    let itemTypeRawValue = barButtonItem?.value(forKey: "systemItem") as! Int

    // 2
    XCTAssertEqual(UIBarButtonSystemItem(rawValue: itemTypeRawValue), UIBarButtonSystemItem.add)
}

//3
func testAddButtonPresentsAddItemViewController() {

    XCTAssertNil(controller.presentedViewController)

    // 4
    guard let addButton = controller.navigationItem.rightBarButtonItem,
        let target = addButton.target,
        let action = addButton.action else {
            return XCTFail("Controller should have a right bar button item with a target and an action")
    }

    UIApplication.shared.keyWindow?.rootViewController = controller

    // 5
    XCTAssertEqual(target.identifier, "presentInputViewController")

    // 6
    target.performSelector(
        onMainThread: action,
        with: addButton,
        waitUntilDone: true
    )

    // 7
    guard let inputViewController = controller.presentedViewController as? InputViewController else {
        return XCTFail()
    }

    XCTAssertNotNil(inputViewController.titleTextField)
}