pytest-mock
Thin-wrapper around the mock package for easier use with pytest
Decision gist · record as of 2026-08-14
Yes. pytest-mock is a standard, actively maintained tool in the pytest ecosystem with no known vulnerabilities, permissive licensing, and minimal install friction. If you write pytest tests and need to mock objects, this plugin eliminates boilerplate and integrates cleanly with pytest's fixture system—it's a near-universal choice for pytest-based projects.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires pytest to be installed; Python 3.9 or later.
- Low friction: pure Python wheel with only pytest as a runtime dependency.
- Active maintenance with recent releases and 2037 repository stars; last commit on 2026-08-13 signals ongoing development.
License · maintenance · safety
MIT (permissive) — MIT license is permissive, allowing use in commercial and private projects with minimal restrictions—only attribution required.
last release 2025-09-16 (332 days) · last repo commit 2026-08-13 · 2,037 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 105,035,819 downloads/mo, #329 on PyPI
Alternatives
Verify before relying
pip install pytest-mock
import os
from pytest_mock import MockerFixture
def test_example(mocker: MockerFixture):
mocker.patch('os.remove')
os.remove('file')
os.remove.assert_called_once_with('file')- Whether the spy and stub utilities offer advantages over standard mock.patch usage patterns.
- Performance characteristics when used in large test suites with many patches.
What it is and what it does
pytest-mock is a pytest plugin that wraps the mock library's patching API into a convenient fixture called `mocker`. Instead of manually managing patches and cleanup in your tests, you inject the mocker fixture and call methods like `mocker.patch()` to replace objects; pytest automatically undoes the patches after each test completes. The plugin also provides `spy` and `stub` utilities and uses pytest's introspection to give clearer output when comparing mock calls.
It's designed for developers writing pytest test suites who want to mock external dependencies—filesystem calls, network requests, database operations—without the boilerplate of manual setup and teardown. The single runtime dependency is pytest itself, making it a lightweight addition to any pytest workflow.
Use it for
- Mock filesystem operations like os.remove in unit tests without affecting the actual filesystem.
- Patch external API calls to test error handling and edge cases without hitting real endpoints.
- Spy on method calls to verify that internal functions were invoked with expected arguments.
- Stub out database operations during testing to isolate business logic from persistence layers.
- Replace time.time or datetime.now in tests to verify time-dependent behavior deterministically.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
pytest-mock is a standard, actively maintained tool in the pytest ecosystem with no known vulnerabilities, permissive licensing, and minimal install friction. If you write pytest tests and need to mock objects, this plugin eliminates boilerplate and integrates cleanly with pytest's fixture system—it's a near-universal choice for pytest-based projects.
Install
pytest-mock on PyPI
Before you install
Low friction: pure Python wheel with only pytest as a runtime dependency. Active maintenance with recent releases and 2037 repository stars; last commit on 2026-08-13 signals ongoing development.
Requires pytest to be installed; Python 3.9 or later.
License in practice
MIT license is permissive, allowing use in commercial and private projects with minimal restrictions—only attribution required.
Quickstart
pip install pytest-mock
import os
from pytest_mock import MockerFixture
def test_example(mocker: MockerFixture):
mocker.patch('os.remove')
os.remove('file')
os.remove.assert_called_once_with('file')Verify before relying
- Whether the spy and stub utilities offer advantages over standard mock.patch usage patterns.
- Performance characteristics when used in large test suites with many patches.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=3.9 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 1 packagepytest |
| Maintenance | Actively maintained 332 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 105,035,819 / month, #329 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableFramework :: PytestIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: Python :: 3Programming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.9Topic :: Software Development :: Testing |
Evidence: pytest_mock-3.15.1-py3-none-any.whl
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See also flexmock · kgb · pytest-stub · mockito · pytest-astropy · stubs · mock-open · testfixtures · pytest-sftpserver · wiremock