XCTest framework basics in Swift - Mini Project: Build & Apply

XCTest framework basics

📖 Scenario: You are building a simple calculator app and want to make sure the addition function works correctly. To do this, you will write tests using the XCTest framework in Swift.

🎯 Goal: Learn how to create a test case class, write a test method using XCTest, and run the test to check if the addition function returns the correct result.

📋 What You'll Learn

Create a test case class inheriting from XCTestCase

Write a test method starting with test

Use XCTAssertEqual to check the addition result

Run the test and print the result

💡 Why This Matters

🌍 Real World

Testing code ensures your app works correctly before users see it. XCTest is the standard way to write tests in Swift apps.

💼 Career

Many software jobs require writing automated tests. Knowing XCTest helps you write reliable Swift code and work well in teams.

1

Create the addition function

Create a function called add that takes two Int parameters named a and b and returns their sum as an Int.

Swift

# Create the add function
// Your code here

Need a hint?

Define a function with two parameters and return their sum using return a + b.

2

Create a test case class

Create a class called CalculatorTests that inherits from XCTestCase.

Swift

func add(a: Int, b: Int) -> Int {
    return a + b
}

// Create CalculatorTests class inheriting from XCTestCase
// Your code here

Need a hint?

Use class CalculatorTests: XCTestCase { } to create the test case class.

3

Write a test method for addition

Inside the CalculatorTests class, write a test method called testAdd that calls add(a: 2, b: 3) and uses XCTAssertEqual to check if the result equals 5.

Swift

import XCTest

func add(a: Int, b: Int) -> Int {
    return a + b
}

class CalculatorTests: XCTestCase {
    // Write testAdd method
    // Your code here
}

Need a hint?

Define a method starting with test, call add, and use XCTAssertEqual to compare.

4

Run the test and print the result

Add code to run the test suite for CalculatorTests and print "All tests passed!" if the test succeeds.

Swift

import XCTest

func add(a: Int, b: Int) -> Int {
    return a + b
}

class CalculatorTests: XCTestCase {
    func testAdd() {
        let result = add(a: 2, b: 3)
        XCTAssertEqual(result, 5)
    }
}

// Run the test suite and print result
// Your code here

Need a hint?

Use XCTMain with testCase and print the success message.