IOS Unit Testing Code Coverage

LoginSpec.swift

import XCTest

class LoginSpec: XCTestCase {
    
    var login: LoginViewModel?

    override func setUp() {
        super.setUp()
        login = LoginViewModel()
        print("\n Method Calling \n")
    }
    
    override func tearDown() {
        // Put teardown code here. This method is called after the invocation of each test method in the class.
        super.tearDown()
    }
    
    func testExample() {
        let isLoginSuccess = login?.login(userName: "Damodar", password: "password")
        XCTAssertEqual(isLoginSuccess, true, "Username or password is wrong")
        // This is an example of a functional test case.
        // Use XCTAssert and related functions to verify your tests produce the correct results.
    }
    
    func testPerformanceExample() {
        // This is an example of a performance test case.
        self.measure {
            // Put the code you want to measure the time of here.
        }
    }
    
}

LoginViewModel

import Foundation

class LoginViewModel {
    
    func login(userName: String, password: String) -> Bool {
       
        if  userName.characters.count > 0 && password.characters.count > 0 {
            return true
        }
        return false
    }

}

ViewController.swift

import UIKit
class ViewController: UIViewController {

    @IBOutlet weak var textFieldName        : UITextField!
    @IBOutlet weak var textFieldPassword    : UITextField!
    @IBOutlet weak var submitButton         : UIButton!

    let loginModel = LoginViewModel()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
    @IBAction func submitAction(sender: UIButton) {
        
        let isValidLogin = loginModel.login(userName: (self.textFieldName?.text)!, password: (self.textFieldPassword?.text)!)
            assert(isValidLogin == true, "Login failed ")
        
    }

}