Unit Testing within Swift Playground

Sep 17, 2023

Creating unit tests in Swift Playground is an easy way to double-check that you’re getting the outcome you expect when developing new features.

In this example, I recreated the fizzbuzz challenge and ran it through multiple tests to ensure it was working as intended. The bottom line executes all of my tests within the FizzBuzzTests class.

import Foundation
import XCTest

class FizzBuzzTests: XCTestCase {
    
    let fizzArray = [3, 6, 9, 12, 18, 21, 24, 27]
    let buzzArray = [5, 10, 20, 25, 35, 40, 50, 55]
    let fizzbuzzArray = [15, 30, 45, 60, 75, 90, 105, 120]
    
    func testFizz() {
        for i in fizzArray {
            let result = fizzbuzz(number: i)
            XCTAssertEqual(result, "Fizz")
        }
    }
    
    func testBuzz() {
        for i in buzzArray {
            let result = fizzbuzz(number: i)
            XCTAssertEqual(result, "Buzz")
        }
    }
    
    func testFizzBuzz() {
        for i in fizzbuzzArray {
            let result = fizzbuzz(number: i)
            XCTAssertEqual(result, "FizzBuzz")
        }
    }
}

func fizzbuzz(number: Int) -> String {
    switch (number % 3 == 0, number % 5 == 0) {
    case (true, false):
        return "Fizz"
    case (false, true):
        return "Buzz"
    case (true, true):
        return "FizzBuzz"
    case (false, false):
        return String(number)
    }
}

FizzBuzzTests.defaultTestSuite.run()