Testing Your Flask App(Part 6): Debug Like a Pro

Introduction

Your app works on your machine. But does it work everywhere? Testing catches bugs before users do.

What You'll Learn

How to:

• Write unit tests
• Debug Flask errors
• Use print statements effectively
• Handle common bugs

Prerequisites

• Flask basics
• Part 1-5 knowledge
• 20 minutes

Step 1: Unit Testing Basics

import unittest

class TestApp(unittest.TestCase):
    def test_homepage(self):
        response = app.test_client().get('/')
        self.assertEqual(response.status_code, 200)

Step 2: Test Database

def test_create_entry(self):
    util.save_entry("Test", "Content")
    entry = util.get_entry("Test")
    self.assertEqual(entry, "Content")

Step 3: Debug Mode

if __name__ == '__main__':
    app.run(debug=True)

Debug mode shows errors clearly and auto-reloads.

Step 4: Print Debugging

def new_page(request):
    print(f"Title: {title}")  # See value
    print(f"Content: {content}")
    util.save_entry(title, content)

Common Bugs

1. Not checking if entry exists
2. Not validating input
3. Database connection issues

Conclusion

Testing = fewer bugs. Debug mode = faster fixes. Print statements = your best friend.

sorry friends I couldn't upload posts recently as I was working on a personal project