Testing & Mocking Packages
Testing frameworks, assertion libraries, and mocking tools for writing reliable unit, integration, and end-to-end tests (testify, pytest, Vitest).
Packages in Testing & Mocking
Kind
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pytest
The Python testing framework that makes writing small tests easy and scales to complex functional test suites.
pluggy
The minimalist, production-ready plugin and hook system that powers pytest, tox, and devpi
Faker
A Python library that generates realistic fake data for testing, seeding, and anonymizing datasets across 70+ locales.
hypothesis
Property-based testing for Python that generates edge cases and shrinks failures to their simplest reproducing example.
fake-useragent
Up-to-date user-agent string faker backed by a real-world browser usage database, bundled offline.
fakeredis
A pure-Python, in-memory implementation of the Redis protocol for testing.
pytest-order
Pytest plugin for running tests in a specific, controllable order
behave
A Python behavior-driven development framework that runs Gherkin feature files against step definitions written in plain Python.
testcontainers-python
Throwaway Docker containers for real integration tests, driven straight from Python.
pytest-html
A pytest plugin that turns your test run into an interactive, shareable HTML report.
mock
The rolling backport of Python's unittest.mock library
factory_boy
A versatile test fixtures replacement for Python, providing declarative factories for building complex test objects.
VCR.py
Record and replay HTTP interactions to speed up tests
DeepEval
A Pytest-like open-source framework for unit-testing and evaluating LLM applications with research-backed metrics.
pywinauto
A Python library that drives Windows GUI apps by sending mouse, keyboard, and text-based actions to dialogs and controls.
pytest-sugar
A pytest plugin that replaces the default test runner output with a live progress bar, instant failure display, and colorized results.
python-devtools
Python's missing debug print command, plus pretty formatting, timing, and pytest helpers.
time-machine
Travel through time in your Python tests by mocking datetime and time at the C level.
pytest-flask
A pytest plugin with ready-made fixtures for testing Flask applications end to end.
aiosmtpd
An asyncio-based SMTP and LMTP server implementation for Python, built to mock mail servers in tests and run lightweight custom relays.
unittest-xml-reporting
A unittest test runner that saves results as xUnit/JUnit XML for CI systems to consume.
Cucumber Expressions
A human-readable alternative to regular expressions for matching Gherkin step text
wiremock
Python client and Testcontainers integration for driving a WireMock server from tests
kgb
Function spies for Python unit tests that intercept, record, and reroute calls without heavy-handed mocking.
