Can anyone give me an example about unit testing in iOS Swift? - ios

Question

I am new in iOS development and want to learn unit testing. I want to add two numbers using text fields and show the result in a label when clicking on the action. Can anyone suggest me how to make a unit test for this?

Answer 1

This is a short example, but you should always try multple different variations as if it would be text instead of numbers and negative numbers, numbers that is higher than int etc...
class AddingViewController: UIViewController {
var sum = 0
let textField1 = UITextField()
let textField2 = UITextField()
let button = UIButton()
override func viewDidLoad() {
super.viewDidLoad()
button.addTarget(self, action: #selector(addNumbers), for: .touchUpInside)
}
#objc func addNumbers() {
guard let number1 = Int(textField1.text!), let number2 = Int(textField2.text!) else {
return
}
sum = number1 + number2
}
}
class TestAddingViewController {
let vc = AddingViewController()
func testAddNumbers() {
let number1 = 1
let number2 = 2
let sum = number1 + number2
vc.textField1.text = "\(number1)"
vc.textField2.text = "\(number2)"
vc.button.sendActions(for: .touchUpInside)
XCTAssertEqual(sum, vc.sum)
}
}
If viewController is from storyboard you call it as you normally call storyboard viewControllers
let storyboard = UIStoryboard(name: "MyStoryboardName", bundle: nil)
let controller = storyboard.instantiateViewController(withIdentifier: "someViewController")
And the textfields + button will be #outlets and the button action will be an #IBAction and not #objc func

Answer 2

Here is my view controller class:
import UIKit
class ViewController: UIViewController {
// MARK: ▼▼▼ IBOutlets ▼▼▼
#IBOutlet weak var lblAnswer: UILabel!
// MARK: ▼▼▼ Lifecycle methods ▼▼▼
override func viewDidLoad() {
super.viewDidLoad()
lblAnswer.text = "\(calculateSum(num1: 5, num2: 10))"
}
// MARK: ▼▼▼ Methods ▼▼▼
func calculateSum(num1: Int, num2: Int) -> Int {
return (num1 + num2)
}
}
And for the unit test class I have:
import XCTest
#testable import Test
class TestTests: XCTestCase {
// MARK: ▼▼▼ Variables ▼▼▼
var num1: Int?
var num2: Int?
var testClass: ViewController?
// This is used to initialise your code:
override func setUp() {
testClass = ViewController()
num1 = 10
num2 = 10
}
// This runs when test is complete:
override func tearDown() {
testClass = nil
num1 = nil
num2 = nil
}
// Should begin with test so that it is recognised:
func testSumFunction() {
let sum = testClass!.calculateSum(num1: num1!, num2: num2!)
// The sum should be 20 for this to pass.
XCTAssertTrue(sum == 20)
}
}
If the logic of the function is changed and answer is not equal to 20 then this test will fail.