Modern tooling
uv, ruff, pyproject.toml, packaging, and current Python project workflows.
How to Generate a Mock Rollbar Error Report in Python
Create a realistic fake Rollbar error report with random timestamps, levels, messages, and counts for testing and demos.
import json
import random
import time
from datetime import datetime, timedelta
def mock_rollbar_report(n_errors=5):
messages = [
"TypeError: unsupported operand type(s) for +: 'int' and 'str'",
"KeyError: 'user_id'",
"ValueError: invalid literal for int() with base 10: 'abc'",
"At…How to Run Coverage Report and Generate HTML in Python
Use the coverage module to measure test coverage, save the report, and generate an HTML report in Python.
import coverage
import unittest
def add(a, b):
return a + b
class TestAdd(unittest.TestCase):
def test_add_positive(self):
self.assertEqual(add(2, 3), 5)
if __name__ == "__main__":
cov = coverage.Coverage(source=["__main__"])
cov.start()
suite = unittest.defaultTestLoader.loadTestsFro…Browse by section
Each section groups closely related Python snippets.
Modern tooling — Python code examples
What you will find here
This page collects modern tooling snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
Samples vs tutorials and challenges
Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.