Lesson 5: Swift setup and first program: Testing focus

Concept Explanation

"Swift setup and first program: Testing focus" is a standalone Beginner Swift lesson designed to help you practice one idea in depth. You will work through a practical coding task, verify the behavior of your solution, and learn how small tests make your code more reliable. The lesson centers on the Beginner Swift skill of testing focus in Swift setup and first program. Along the way, you will use Swift patterns that commonly appear in iOS and macOS development while improving code clarity, confidence, and maintainability. Lesson fingerprint: swift:Swift Beginner:Swift setup and first program:beginner-swift-setup-and-first-program-5:5.

Where to Put the Code

1. Define color and position variables at the top.
2. Create shape drawing or placement logic in the middle.
3. Render output (print, canvas, SVG, or styled block) at the end.

Command Reference

• Relate the code in this lesson to the core testing focus skill.
• Document one decision using ideas from protocol-oriented, type-safe application development.
• Identify where this pattern appears in realistic development work.
• Check the result and record the expected behavior.

Step-by-step Guide

1. Finish with a short checklist for correctness and clarity.
2. Type the starter code yourself and run it without changes.
3. Summarize the target outcome in one sentence.
4. Refactor for readability and maintainability using safe optionals, clear APIs, and maintainable app architecture.
5. Test one normal case and one edge case.

Practice Exercises

• Rewrite the logic in a cleaner style without changing the result.
• Add validation rules and explain three design decisions.
• Extend the solution so it fits a more realistic workflow.

Coding Challenges

• Implement two versions and compare their maintainability and complexity.
• Scale the solution to a larger input set and review how it behaves.

Mini Practice Tasks

• Rename variables or functions to make their purpose clearer.
• Create a shorter version of the solution for lesson unit 5.
• Write one quick test, or use a short manual checklist, and run it.