How to do Unit Test of segue in iOS 9

Question

I had searched over the Internet for a couple of days without exact example hit my case.
For simple class. I had created Unit test.

I want to do Unit Testing on segue and unwind segue.

How can I do that?
ProfileTableViewController is a controller of left-hand-sided.
SeeDetailViewController is a controller of right-hand-sided.
ProfileTableViewController :

import UIKit

class ProfileTableViewController: UITableViewController {

    var profiles = [Profile]();
    var profileNew : Profile?;

    override func viewDidLoad() {
        super.viewDidLoad()
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 1;
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return profiles.count;
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cellIdentifier = "ProfileTableViewCell";
        let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! ProfileTableViewCell
        let profile = profiles[indexPath.row];
        cell.nameLabel.text = profile.name;
        cell.accessoryType = UITableViewCellAccessoryType.DisclosureIndicator

        return cell
    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        tableView.deselectRowAtIndexPath(indexPath, animated: true);
        let row = indexPath.row;
        print("Row:\(row)");
        print(profiles[row].name , profiles[row].age);
        performSegueWithIdentifier("segueTest", sender: row);
    }

    // Mark: Actions
    @IBAction func backFromOtherController(segue: UIStoryboardSegue) {
        NSLog("I'm back from other controller!")
        print(profileNew?.name);

        //add the new profile
        if(profileNew != nil){
            profiles += [profileNew!];
            //update the tableview
            tableView.reloadData();

        }

    }
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
        if(segue.identifier == "segueTest"){
            let svc = segue.destinationViewController as! SeeDetailViewController
            let rowid = sender as! Int;
            svc.NamePassed = profiles[rowid].name;
            svc.AgePassed = profiles[rowid].age;
            svc.DescPassed = profiles[rowid].description;
            svc.SpecPassed = profiles[rowid].specialty;

        }
    }
}

SeeDetailViewController :

import UIKit

public class SeeDetailViewController: UIViewController {

    // Mark: Properties
    @IBOutlet weak var NameLabel: UILabel!
    @IBOutlet weak var AgeLabel: UILabel!
    @IBOutlet weak var SpecialtyLabel: UILabel!
    @IBOutlet weak var descTextView: UITextView!

    var NamePassed : String!;
    var AgePassed : Int!;
    var SpecPassed : String!;
    var DescPassed : String!;

    override public func viewDidLoad() {
        super.viewDidLoad()
        NameLabel.text = NamePassed;
        let myString = String(AgePassed);
        AgeLabel.text = myString;
        SpecialtyLabel.text = SpecPassed;
        descTextView.text = DescPassed;
    }

    override public func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // Mark: Actions
    @IBOutlet weak var HitCall: UIButton!

    @IBAction func alertControllerAction(sender: AnyObject) {
        if(sender.tag == 0 ){
            print("Touch down!");
            let alertController = UIAlertController(title: "Hello!", message: "My name is \(NamePassed)", preferredStyle: .Alert)

            let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel) { (action:UIAlertAction!) in
                print("you have pressed the Cancel button");
            }
            alertController.addAction(cancelAction)

            let OKAction = UIAlertAction(title: "OK", style: .Default) { (action:UIAlertAction!) in
                print("you have pressed OK button");
            }
            alertController.addAction(OKAction)

            self.presentViewController(alertController, animated: true, completion:nil)
        }
    }
    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    // Get the new view controller using segue.destinationViewController.
    // Pass the selected object to the new view controller.
    }
    */

}

Answer 1

As said in this post you can use undocumented API to get the segues. And than you can write your tests like this:

class MyViewControllerTests: XCTestCase {

    var SUT: MyViewController!

    override func setUp() {
        super.setUp()

        SUT = UIStoryboard(name: "MyStoryboard", bundle: Bundle(for: MyViewController.self)).instantiateViewController(withIdentifier:String(describing: MyViewController.self)) as! MyViewController
        let _ = SUT.view
    }

    override func tearDown() {
        SUT = nil
        super.tearDown()
    }

    // Mark: - Test Methods

    func testSegues() {
        let identifiers = segues(ofViewController: SUT)
        XCTAssertEqual(identifiers.count, 2, "Segue count should equal two.")
        XCTAssertTrue(identifiers.contains("ExitSegueIdentifier"), "Segue ExitSegueIdentifier should exist.")
        XCTAssertTrue(identifiers.contains("ShowDetailViewController"), "Segue ShowDetailViewController should exist.")
    }

    // Mark: - Helper Methods

    func segues(ofViewController viewController: UIViewController) -> [String] {
        let identifiers = (viewController.value(forKey: "storyboardSegueTemplates") as? [AnyObject])?.flatMap({ $0.value(forKey: "identifier") as? String }) ?? []
        return identifiers
    }

}

Answer 2

An easy way to unit test a view controller segue (although it breaks a bit of abstraction) is the following:

1. Create a variable, say, calledSegue which initially has a nil value.
2. Override performSegueWithIdentifier: function of your target view controller so that it sets calledSegue to the called segue identifier. Make sure that you also call super.performSegueWithIdentifier: within the overridden function in order to retain the original function's behaviour.
3. Create a unit test that check that calledSegue is set to the expected segue identifier under a test condition.