Automatic mock fixtures for pytest

conftest.py

import pytest
from _pytest.monkeypatch import MonkeyPatch
from mock import Mock

BUILTINS = set(dir(__builtins__))


def _mock(monkeypatch, name, module):
    if name in BUILTINS:
        module = __builtins__
    ret = Mock()
    monkeypatch.setattr(module, name, ret)
    return ret


@pytest.hookimpl(hookwrapper=True)
def pytest_runtest_protocol(item, nextitem):
    monkeypatch = MonkeyPatch()
    for fname in item.fixturenames:
        if fname.startswith("mock_") and fname not in item.funcargs:
            item.funcargs[fname] = _mock(monkeypatch, fname[5:], item.module.MODULE)
    yield
    monkeypatch.undo()