Reference library

System design patterns

Sharding, load balancing, CAP tradeoffs, and scaling patterns — interview and production ready.

1 match
System design patterns medium

Mock Unit of Work commit and rollback in Python

Verify that a Unit of Work pattern commits on success and rolls back on failure using unittest.mock in Python.

unit-of-work mocking testing
Python 
from unittest import mock


class UnitOfWork:
    def __init__(self):
        self.committed = False
        self.rolled_back = False

    def commit(self):
        self.committed = True
        print("Commit executed")

    def rollback(self):
        self.rolled_back = True
        print("Rollback executed")


def b…
13 0 Open

Browse by section

Each section groups closely related Python snippets.

System design patterns — Python code examples

What you will find here

This page collects system design patterns 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.

Related coding tools

Free online Python IDE Write and run Python in your browser — no install. Free Python code formatter Format with autopep8 — side-by-side PEP 8 cleanup. Python code samples Copy-ready snippets to study and run in the IDE.