Test-driven development in Swift in iOS Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Test-Driven Development (TDD)?

TDD is a way to write software where you first write a test that fails, then write code to make it pass, and finally clean up the code. It helps catch bugs early and improves design.

beginner

In Swift, which framework is commonly used for writing unit tests?

XCTest is the standard framework in Swift for writing and running unit tests.

beginner

What are the three main steps in the TDD cycle?

1. Write a failing test.<br>2. Write code to pass the test.<br>3. Refactor the code to improve it without breaking the test.

intermediate

Why should tests be written before the actual code in TDD?

Writing tests first helps you think about what the code should do, ensures requirements are clear, and prevents writing unnecessary code.

beginner

How do you run tests in Xcode for a Swift project?

You can run tests by pressing Command+U or by clicking the diamond icon next to the test method or class in Xcode.

What is the first step in Test-Driven Development?

A Write a test that fails

B Write the code to solve the problem

C Refactor the existing code

D Run all tests to check for errors

In TDD, you start by writing a test that fails to define what the code should do.

Which Swift framework is used to write unit tests?

A XCTest

B SwiftUI

C CoreData

D Combine

XCTest is the built-in framework for unit testing in Swift.

What does the 'Refactor' step in TDD mean?

A Add new features

B Fix bugs found by tests

C Improve code without changing behavior

D Delete old tests

Refactoring means cleaning up code to make it better without changing what it does.

Why is TDD helpful in app development?

A It makes the app run faster

B It helps catch bugs early and improves code design

C It removes the need for documentation

D It automatically writes code for you

TDD helps find bugs early and encourages writing clean, well-designed code.

How do you run all tests in Xcode?

A Close and reopen the project

B Press Command+R

C Click the Play button

D Press Command+U

Command+U runs all tests in the current Xcode project.

Explain the Test-Driven Development cycle and why it is useful in Swift app development.

Think about the order of writing tests and code, and how it helps improve quality.

Describe how to write and run a simple unit test in Swift using XCTest.

Remember the basic structure of a test and how to check results.