mockito 2.0.4

Spying framework

Mockito is a spying framework originally based on the Java library with the same name. (Actually we invented the strict stubbing mode back in 2009.)

Install

pip install mockito

Quick Start

90% use case is that you want to stub out a side effect.

from mockito import when, mock, unstub

when(os.path).exists('/foo').thenReturn(True)

# or:
import requests  # the famous library
# you actually want to return a Response-like obj, we'll fake it
response = mock({'status_code': 200, 'text': 'Ok'})
when(requests).get(...).thenReturn(response)

# use it
requests.get('http://google.com/')

# clean up
unstub()

Read the docs

http://mockito-python.readthedocs.io/en/latest/

Breaking changes in v2

Two functions have been renamed:

• verifyNoMoreInteractions is deprecated. Use ensureNoUnverifiedInteractions instead.

Although verifyNoMoreInteractions is the name used in mockito for Java, it is a misnomer over there too (imo). Its docs say “Checks if any of given mocks has any unverified interaction.”, and we make that clear now in the name of the function, so you don’t need the docs to tell you what it does.

• verifyNoUnwantedInteractions is deprecated. Use verifyExpectedInteractions instead.

The new name should make it clear that it corresponds to the usage of expect (as alternative to when).

Context managers now check the usage and any expectations (if you used expect) on exit. You can disable this check by setting the environment variable MOCKITO_CONTEXT_MANAGERS_CHECK_USAGE to “0”. Note that this does not disable the check for any explicit expectations you might have set with expect.

This roughly corresponds to the verifyStubbedInvocationsAreUsed contra the verifyExpectedInteractions functions.

• The (limited) in-order verification mode (inorder.verify(…)) is deprecated in favor of InOrder(…). InOrder support true ordered, cross-mock verification.

New in v2

First-class async/await and property/descriptor support. Chaining. InOrder. Enhanced captor, new patch_attr and patch_dict. Refer the changelog<https://mockito-python.readthedocs.io/en/latest/changes.html>.

Development

I use uv, and if you do too: you just clone this repo to your computer, then run uv sync in the root directory. Example usage:

uv run pytest

To run the full supported Python matrix in parallel:

uv run python scripts/run-pytest-matrix.py

To run only selected versions:

uv run python scripts/run-pytest-matrix.py -p 3.8 -p 3.14

The matrix runner keeps per-version virtual environments in .runner/ (.venv-3.8, etc.) so runs can execute safely in parallel while only outcome-*.txt files are wiped each run. Use --recreate-envs to rebuild those environments.

Note: development and docs tooling target Python >=3.12, while the library itself supports older Python versions at runtime.

To install everything (all dependency groups, Python >=3.12), run:

uv sync --all-groups

Start the sphinx server:

uv run sphinx-autobuild docs docs/_build/html