pytest-socket

A plugin to use with Pytest to disable or restrict socket calls during tests to ensure network calls are prevented.

Features

Disables all network calls flowing through Python's socket interface.

Requirements

Pytest 6.2.5 or greater

Installation

You can install pytest-socket via pip from PyPI:

pip install pytest-socket

or add to your pyproject.toml for poetry:

[tool.poetry.dev-dependencies]
pytest-socket = "*"

Usage

Run pytest --disable-socket, tests should fail on any access to socket or libraries using socket with a SocketBlockedError.

To add this flag as the default behavior, add this section to your pytest.ini:

[pytest]
addopts = --disable-socket

or add this to your setup.cfg:

[tool:pytest]
addopts = --disable-socket

or update your conftest.py to include:

from pytest_socket import disable_socket

def pytest_runtest_setup():
    disable_socket()

If you exceptionally want to enable socket for one particular execution pass --force-enable-socket. It takes precedence over --disable-socket.

To enable Unix sockets during the test run (e.g. for async), add this option:

[pytest]
addopts = --disable-socket --allow-unix-socket

To enable specific tests use of socket, pass in the fixture to the test or use a marker:

def test_explicitly_enable_socket(socket_enabled):
    assert socket.socket(socket.AF_INET, socket.SOCK_STREAM)


@pytest.mark.enable_socket
def test_explicitly_enable_socket_with_mark():
    assert socket.socket(socket.AF_INET, socket.SOCK_STREAM)

To allow only specific hosts per-test:

@pytest.mark.allow_hosts(['127.0.0.1'])
def test_explicitly_enable_socket_with_mark():
    assert socket.socket.connect(('127.0.0.1', 80))

or for whole test run

[pytest]
addopts = --allow-hosts=127.0.0.1,127.0.1.1

Frequently Asked Questions

Q: Why is network access disabled in some of my tests but not others?

A: pytest's default fixture scope is "function", which socket_enabled uses. If you create another fixture that creates a socket usage that has a "higher" instantiation order, such as at the module/class/session, then the higher order fixture will be resolved first, and won't be disabled during the tests. Read more in this excellent example and more about pytest fixture order here.

This behavior may change in the future, as we learn more about pytest fixture order, and what users expect to happen.