How to Test AI-Generated Code

AI Writes Code, You Play Detective

When you ask an AI to write code, it often looks like it works perfectly — until it doesn't. AI generates code by guessing what words should come next based on patterns it has seen before. It doesn't actually think about whether the code makes sense in your specific situation.

Think of it like a student who memorized the answers to a math test. They can write down the right numbers fast, but sometimes they put the decimal in the wrong place or forget to carry a number. The test still looks done, but the answers are wrong.

That's why testing matters. You need to check that the AI's code actually does what you asked for, handles all the tricky cases, and doesn't break anything else.

Cool Features Mean Nothing If They Break

Here's the thing about AI-generated code: it often looks amazing on the surface. The buttons are styled. The animations work. It seems done. But under the hood, there might be hidden problems that only show up when real users try to use it.

Maybe the AI wrote code that works for normal names, but breaks if someone has an apostrophe in their name (like "O'Connor"). Maybe it works on your computer but crashes on someone else's phone. Maybe it shows the right answer 99% of the time but deletes data in that 1% case nobody thought to try.

The Four Steps of Testing AI Code

Testing AI code doesn't have to be complicated. You just need a clear way to check that the code does what you want. Here's a simple four-step process anyone can follow:

What counts as "weird inputs"?

• Empty input: What if someone clicks submit without typing anything?
• Really long text: What if someone pastes an entire essay into a name field?
• Special characters: What if someone uses symbols like % or < or " in their input?
• Numbers at the boundaries: What happens with 0, -1, or 999999999?

Testing a Name Greeter

Imagine you asked an AI to build a page that says "Hello, [Name]!" and the AI wrote this code:

function greet(name) {
  // Greet the user by name
  let message = "Hello, " + name + "!";
  return message;
}

console.log(greet("Alice"));
// Output: Hello, Alice!

This looks correct! You test it with "Alice" and it prints "Hello, Alice!" — perfect, right? Not so fast. Here are the edge cases you should try:

console.log(greet(""));
// Output: Hello, !

console.log(greet("<script>bad()</script>"));
// Output: Hello, <script>bad()</script>!
// ⚠️ This is a security risk — it could run harmful code!

console.log(greet("Bobby'; DROP TABLE users;--"));
// Output: Hello, Bobby'; DROP TABLE users;--!
// ⚠️ This looks like a database attack attempt!

Suddenly that "perfect" code has serious problems. Empty names look weird, and special characters could be used for attacks. You'd report these back to the AI: "Fix this — if the name is empty, say 'Hello, stranger!' If it has special characters, clean them up so nobody can inject code."

Knowledge Check

Test what you learned with this quick quiz.