First App.
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CHAPTER 06Lesson 19 of 36

Write a simple test checklist

Testing means trying the things a real person will do and checking the result.

In Codex5 min read & do
By the end of this lesson

Have a short checklist you can repeat after every change.

Let’s do this

  1. 1
    In Codex

    Write down the normal journey

    Start with your definition of done. List opening the app, doing its main job and seeing the expected result. Use your own words, such as “Add a plant and see it in my list”.

  2. 2
    In Codex

    Add the awkward cases

    Try an empty field, a long name, cancelling, deleting and reopening the app. If the app uses the internet, include no connection. If it has accounts, include signing out and trying another user.

  3. 3
    In Codex

    Try different viewing conditions

    Use a small and a large iPhone simulator. Increase text size, try VoiceOver and check any light or dark appearance your app supports. Make sure the keyboard does not cover the Save button.

  4. 4
    In Codex

    Ask Codex for repeatable checks

    Codex can write automated tests for important behaviour, such as saving a record or enforcing access rules. Ask it to run them and explain the result. Still try the app yourself: a passing code test cannot tell you whether the screen feels clear.

Device Hub window showing an iPhone simulator running Apple’s Landmarks app in landscape.View larger
Apple’s example of an app in the simulator. The guide illustrates iOS 27; use the current stable simulator you installed, which may look different.Screenshot source (opens a new tab)

A message for Codex

Create a short, plain-English test checklist for my first iPhone app. Its main job is [describe the problem my app should solve] and its starting features are [choose up to three small features]. Include the normal journey, empty and long input, cancel/delete, persistence, larger text and relevant offline or account cases. Add meaningful automated checks for important behaviour, run them and report what passed, failed or could not be tested.

Make this message fit your idea.

What you should see

You have a checklist with a clear expected result for each action. You know which checks you will repeat after changes.

If you get stuck

Go at your own pace. There is no test to pass.

Checked 7 September 2026. Screens can change; the official guides below have the latest steps.

Run on a simulator or deviceApple’s design guidanceApple’s App Review guidance