View Controller TDD

I am trying to add some unit tests to my project to test view controllers. However I seem to be having problems with seemingly simple things. I have created a sample project which I will refer to. http://ift.tt/1wfUeIB

The sample contains a UINavigationController as the initial view controller. The root view controller of the UINavigationController is FirstViewController. There is a button on FirstViewController that segues to SecondViewController. In SecondViewController there is an empty textfield.

The two tests I am trying to add are:

1) Check button title in FirstViewController is "Next Screen".

2) Check textfield in SecondViewController is empty, "".

I have heard reports of adding your swift files to both the main target and the test target is not good practice. But rather it is better to make whatever you want to access in your tests public and import the main target into the tests. So that is what I have done. (I have also set the "Defines Module" for the main target to YES as that is what I have read in a few articles aswell).

In FirstViewControllerTests I have instantiated the first view controller with the following:

var viewController: FirstViewController!

override func setUp() {
    let storyboard = UIStoryboard(name: "Main", bundle: NSBundle(forClass: self.dynamicType))
    let navigationController = storyboard.instantiateInitialViewController() as UINavigationController
    viewController = navigationController.topViewController as FirstViewController
    viewController.viewDidLoad()
}

And I have added the test:

func testCheckButtonHasTextNextScreen() {
    XCTAssertEqual(viewController.button.currentTitle!, "Next Screen", "Button should say Next Screen")
}

Similarly, for SecondViewControllerTest, I have set it up using:

var secondViewController:SecondViewController!

override func setUp() {
    let storyboard = UIStoryboard(name: "Main", bundle: NSBundle(forClass: self.dynamicType))
    let navigationController = storyboard.instantiateInitialViewController() as UINavigationController
    let firstviewController = navigationController.topViewController as FirstViewController
    firstviewController.performSegueWithIdentifier("FirstToSecond", sender: nil)
    secondViewController = navigationController.topViewController as SecondViewController
    secondViewController.viewDidLoad()
}

And the test:

func testTextFieldIsBlank() {
    XCTAssertEqual(secondViewController.textField.text, "", "Nothing in textfield")
}

They both fail and I am not too sure as to why. My suspicion is that the way I am instantiating the view controllers is not correct. Is the best way to instantiate the view controllers is to use the storyboard (just like it would if it were to run in real life)? Or is it acceptable to be instantiated via:

var viewController = FirstViewController()

What are you guys' experience with TDD and view controllers in swift?

I am using Swift with XCode 6.1.1.

Thanks in advance.