Techniques

Debugging Techniques

• Print Statements: Insert print() statements throughout your code to display the values of variables or expressions at specific points.

  def calculate_sum(a, b):
                print(f"a: {a}, b: {b}")
                sum = a + b
                print(f"Sum: {sum}")
                return sum
            
            result = calculate_sum(10, 20)
            print(f"Result: {result}")
            

  Source: https://docs.python.org/3/library/functions.html#print

• Debuggers: Use a debugger to step through your code line by line, inspect variables, and set breakpoints. Popular debuggers include:

  • pdb (Python Debugger): Built-in debugger, invoked by adding import pdb; pdb.set_trace() to your code.
  • IPython: Interactive shell with debugging features.
  • Visual Studio Code: Integrated Development Environment (IDE) with a built-in debugger.

  import pdb
            
            def calculate_average(numbers):
                total = 0
                for number in numbers:
                    pdb.set_trace()  # Set breakpoint
                    total += number
                average = total / len(numbers)
                return average
            
            numbers = [1, 2, 3, 4, 5]
            result = calculate_average(numbers)
            print(f"Average: {result}")
            

  Source: https://docs.python.org/3/library/pdb.html Source: https://ipython.org/ Source: https://code.visualstudio.com/

• Logging: Implement a logging system to record messages at different severity levels (e.g., DEBUG, INFO, WARNING, ERROR, CRITICAL).

  import logging
            
            logging.basicConfig(level=logging.DEBUG, format='%(asctime)s - %(levelname)s - %(message)s')
            
            def process_data(data):
                logging.debug(f"Processing data: {data}")
                # ... data processing logic ...
                logging.info(f"Data processed successfully.")
            
            data = [1, 2, 3]
            process_data(data)
            

  Source: https://docs.python.org/3/library/logging.html

Testing Techniques

• Unit Tests: Create individual tests for specific functions or modules to verify their correctness.

  import unittest
            
            def add(x, y):
                return x + y
            
            class TestAdd(unittest.TestCase):
                def test_add_positive(self):
                    self.assertEqual(add(2, 3), 5)
            
                def test_add_negative(self):
                    self.assertEqual(add(-2, 3), 1)
            
            if __name__ == '__main__':
                unittest.main()
            

  Source: https://docs.python.org/3/library/unittest.html

• Integration Tests: Test the interaction between different parts of your application.

  # Example integration test for a web application
            import requests
            
            def test_login(self):
                response = requests.post('https://example.com/login', data={'username': 'testuser', 'password': 'testpassword'})
                self.assertEqual(response.status_code, 200)
            

• End-to-End Tests: Verify the complete workflow of your application from start to finish.

  # Example end-to-end test for a web application
            from selenium import webdriver
            
            def test_user_registration(self):
                driver = webdriver.Chrome()
                driver.get('https://example.com/register')
                # ... simulate user registration steps ...
                driver.quit()
            

  Source: https://www.selenium.dev/