Unit Tests Fast AF

Writing unit tests in Swift and Xcode can seem intimidating at first, but it is actually a valuable tool for ensuring the quality and reliability of your code. Not only can unit tests help catch bugs early on in the development process, they can also serve as documentation for your code and make it easier to refactor in the future.

To get started, you will need to have Xcode installed on your computer and create a new project. Once your project is open, go to the File menu and select “New” and then “Target.” From there, choose “iOS” and “Unit Test Bundle.”

Name your test bundle and click “Finish.” This will create a new folder in your project called “Tests” which will contain your unit tests.

Now, let’s write our first test. In the “Tests” folder, create a new Swift file and name it “MyTestClass.” Inside this file, you will need to import XCTest and create a new class that subclasses XCTestCase.

Here’s what your class should look like so far:

import XCTest

class MyTestClass: XCTestCase {

}

Next, we’ll create a function for our test. This function should be marked with the test prefix and should contain the code we want to test. In this example, we'll test a simple function that adds two numbers together.

func testAddition() {
    let result = add(a: 2, b: 3)
    XCTAssertEqual(result, 5)
}

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

To run our test, we’ll need to navigate to the “Product” menu and select “Test.” This will build and run our tests and display the results in the Test Navigator panel.

If our test passes, it will be marked with a green checkmark. If it fails, it will be marked with a red X and the error message will be displayed in the console.

It’s also good practice to include test coverage for edge cases, such as passing in negative numbers or zero. This can help ensure that our function is working correctly in all scenarios.

To wrap up, writing unit tests in Swift and Xcode is a simple and effective way to ensure the reliability of your code. It can save you time and frustration in the long run by catching bugs early on and making it easier to refactor your code.

Citations:

• “Unit Testing in Xcode,” Apple Developer Documentation (https://developer.apple.com/documentation/xcode/unit_testing_applications)
• “Unit Testing Tutorial: Getting Started,” Ray Wenderlich (https://www.raywenderlich.com/5244-unit-testing-tutorial-getting-started)