Testing and Debugging Python Code

What is Testing and Debugging?

Testing and Debugging means testing checks whether code works correctly. Debugging helps find and fix errors.

In real programs, this topic helps in checking code automatically. Learn the idea first, then type the program yourself and compare the output.

Why should you learn this?

• It is useful for checking code automatically.
• It connects with finding wrong output.
• It improves your ability to read, write and debug Python programs.

Important Terms

These terms are used directly in this lesson. Understand them before memorising the code.

Syntax / Basic Pattern

The simple pattern is: prepare data, apply the concept, then show the result.

def add(a, b):
    return a + b
assert add(2, 3) == 5
assert add(-1, 1) == 0
print("All tests passed")

Complete Example Program

def add(a, b):
    return a + b

assert add(2, 3) == 5
assert add(-1, 1) == 0

print("All tests passed")

Expected Output

Program Explanation

• def add(a, b): creates a reusable function.
• return a + b sends a result back from the function.
• assert add(2, 3) == 5 performs the next step of the program logic.
• assert add(-1, 1) == 0 performs the next step of the program logic.
• print("All tests passed") displays information or calculated result on the screen.

Where will you use it?

• Checking code automatically.
• Finding wrong output.
• Improving reliability.

Common Mistakes

• Making code complex when a simple function or class is enough.
• Not handling possible errors or edge cases.
• Mixing project dependencies instead of using a virtual environment.

Practice Tasks

1. Type the program in testing-debugging.py and run it.
2. Change input values or sample data and observe the new output.
3. Create one example related to checking code automatically.
4. Write 5 lines explaining the logic in your own words.

Summary

Testing and Debugging is not a theory-only topic. You should be able to explain the meaning, write the example, run it successfully, and use it in a small practical program.