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Debugging and Testing with AI

Knowledge

Finding Errors with AI Support

Debugging -- finding and fixing errors in code -- is often the most time-consuming part of software development. AI can significantly accelerate this process by interpreting error messages, identifying possible causes, and suggesting solutions.

How AI Helps with Debugging

Interpreting error messages: Stack traces and error messages are often cryptic. AI translates them into understandable language and explains what went wrong:

  • You enter the error message: TypeError: Cannot read properties of undefined (reading 'map')
  • AI explains: "You're trying to call .map() on a variable that is undefined. This typically happens when data hasn't loaded yet or the API returns an unexpected response."
  • AI suggests solutions: null check, optional chaining, or default values

Root cause analysis: For more complex bugs, AI can systematically go through the code and identify possible error sources. You describe the observed vs. expected behavior, and the AI narrows down the cause.

Reproducibility: AI helps identify the conditions under which a bug occurs and suggests minimal reproduction steps.

*Effective Bug Reporting to AI

Describe bugs like this: "Expected: X happens. Actually: Y happens. The error occurs when Z." The more precise the description, the faster the AI finds the cause.

AI-Powered Test Generation

Tests are the insurance that code works correctly. AI can significantly help with writing tests:

Unit tests: AI analyzes a function and generates tests for:

  • Standard cases (happy path)
  • Edge cases (empty lists, null values, extreme numbers)
  • Error cases (invalid inputs, network errors)

Improving test coverage: AI identifies code paths that are not yet tested and suggests appropriate tests.

Generating test data: AI creates realistic test data covering various scenarios -- from typical inputs to edge cases.

Debugging Workflow with AI

Understanding

Debugging Prompts That Work

For error messages:

  • "Here's my code and the error message. Explain what the error means and show me how to fix it: [code + error message]"

For logical errors:

  • "This function should return result X but returns Y instead. Here's the code -- where's the logical error?"

For performance issues:

  • "This code runs too slowly with large datasets. Where are the performance bottlenecks, and how can I optimize?"

For test generation:

  • "Write unit tests for this function. Cover standard cases, edge cases, and error cases."

Test-First with AI

A particularly effective approach: write the tests first and then let the AI generate the implementation.

  1. Describe the desired behavior as test cases
  2. The AI generates tests based on your description
  3. You review and supplement the tests
  4. The AI implements the code that passes all tests

This approach -- known as Test-Driven Development (TDD) -- ensures that the generated code actually does what you expect.

!Review Tests, Not Just Code

AI-generated tests can be false positives: they pass even though they don't actually test anything meaningful. Verify that the tests truly validate the expected behavior and don't just confirm the current implementation.

Application

Take a bug you've had recently (or simulate one by deliberately introducing an error into a script). Copy the faulty code and error message into an AI and follow how it analyzes the cause. Then have it generate a test that ensures the bug doesn't recur. Compare the AI-suggested fix with your own solution.

Reflection

AI makes debugging faster and testing more comprehensive. The combination in particular -- AI finds the bug, you understand the cause, AI writes the test -- is a powerful workflow. What remains important: always understand why an error occurred, not just how it was fixed. Only then will you learn to avoid similar errors in the future.