How to Install `pytest-mock` in Python

v3.15.1 Testing & QA Python >=3.9 MIT

Thin-wrapper around the mock package for easier use with pytest

Install pip install pytest-mock

What is pytest-mock?

Thin-wrapper around the mock package for easier use with pytest

This plugin provides a `` fixture which is a thin-wrapper around the patching API provided by the :

@staticmethod def rm(filename): os.remove(filename)

Besides undoing the mocking automatically after the end of the test, it also provides other nice utilities such as ``, and uses pytest introspection when comparing calls.

PyPI page → Author: Bruno Oliveira <[email protected]>

Quick Start

Minimal example to get started with pytest-mock:

import pytest_mock

print(pytest_mock.__version__)

Installation

pip (standard)

pip install pytest-mock

Virtual environment (recommended)

python -m venv venv
source venv/bin/activate   # Windows: venv\Scripts\activate
pip install pytest-mock

pip3

pip3 install pytest-mock

conda

conda install -c conda-forge pytest-mock

Poetry

poetry add pytest-mock

Dependencies

Installing pytest-mock will also install these packages:

pytest

Verify the Installation

After installing, confirm the package is available:

python -c "import pytest_mock; print(pytest_mock.__version__)"

If this prints a version number, installation succeeded. If you see a ModuleNotFoundError, see the errors section below.

Installation Errors

Common errors when installing pytest-mock with pip.

ModuleNotFoundError: No module named 'pytest_mock'

Cause: The package is not installed in the current Python environment.

Fix: Run pip install pytest-mock. If using a virtual environment, ensure it is activated first.

ModuleNotFoundError: No module named 'pytest_mock' (installed but still failing)

Cause: pip installed the package into a different Python than the one running your script.

Fix: Use python -m pip install pytest-mock to install into the interpreter you are running.

ImportError: cannot import name 'X' from 'pytest_mock'

Cause: The function or class does not exist in the installed version.

Fix: Check the version with pip show pytest-mock and upgrade with pip install --upgrade pytest-mock.

pip: command not found

Cause: pip is not in PATH or Python was not added to PATH during installation.

Fix: Try python -m pip install pytest-mock. On macOS/Linux try pip3.

PermissionError: [Errno 13] Permission denied

Cause: No write access to the system Python package directory.

Fix: Use a virtual environment, or add --user: pip install --user pytest-mock

SSL: CERTIFICATE_VERIFY_FAILED

Cause: pip cannot verify PyPI's SSL certificate — common behind corporate proxies.

Fix: Try: pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org pytest-mock

Recent Releases

Version	Released
`3.15.1` latest	2025-09-16
`3.15.0`	2025-09-04
`3.14.1`	2025-05-26
`3.13.0`	2024-03-21
`3.14.0`	2024-03-21

Full release history on PyPI →

Manage pytest-mock

Upgrade to latest version

pip install --upgrade pytest-mock

Install a specific version

pip install pytest-mock==3.15.1

Uninstall

pip uninstall pytest-mock

Check what is installed

pip show pytest-mock

Last updated: 2026-04-11 • Data from PyPI

How to Install pytest-mock in Python