Unit Testing in XCode (Obj C) With MVVM - objective-c

Question

I'm testing out some MVVM pattern stuff and seem to have gotten myself confused. Hoping someone here can clarify things for me.
So, what I did was set up a project and added a class that is a subclass of NSObject and called it RootViewModel.
Gave it one method:
- (void) rootTest {
NSLog(#"Booyeah!");
}
In ViewController I imported RootViewModel and made an IBOutlet for it.
#import "ViewController.h"
#import "RootViewModel.h"
#interface ViewController ()
#property (weak, nonatomic) IBOutlet UIButton *btnRunModel;
#property IBOutlet RootViewModel* myModel;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self.myModel rootTest];
}
#end
Then in Storyboard I dragged an Object into the ViewController scene, named it RootModel and connected it to the myModel property in ViewController.
Run the app and it works as expected, Booyeah gets logged.
So now here's where I got messed up. I wanted to set up a unit test. So working in the default unit test file I imported ViewController and made it a property and instantiated it in the set up.
#import <XCTest/XCTest.h>
#import "ViewController.h"
#interface ObjectiveVMMVTests : XCTestCase
#property (nonatomic, strong) ViewController* myViewController;
#end
#implementation ObjectiveVMMVTests
- (void)setUp {
[super setUp];
self.myViewController = [[ViewController alloc] init];
}
Then I tried to create a test where I call the rootTest method.
- (void) testRootModel {
[self.myViewController.myModel rootTest];
}
But I get a compiler error saying myViewController has no property myModel. I assumed it would be there, not sure where I messed this up.

Answer 1

In your unit test, you are saying:
#import "ViewController.h"
That's great. So now the unit test knows that this is a class. But that is not where the myModel property is declared. It is declared in ViewController.m, making this a private property.
Move the property declaration into ViewController.h to make it public so the unit test can see it.

Answer 2

Like #matt said, the IBOutlet is not part of the public interface of ViewController. It's private, hidden in the implementation (.m) file.
You have at least two viable options:
Add #property IBOutlet RootViewModel* myModel; to the ViewController.h file to make it part of the public interface;
Add an interface definition to the ObjectiveVMMVTests unit test file that'll satisfy the compiler:
#interface ViewController ()
#property IBOutlet RootViewModel* myModel;
#end
The implementation of the -(RootViewModel*)myModel getter is there anyway, the compiler just needs to know that ViewController does respond to the message. (You could use performSelector if you weren't interested in the returned object.)