pyfakefs

pyfakefs implements a fake file system that mocks the Python file system modules. Using pyfakefs, your tests operate on a fake file system in memory without touching the real disk. The software under test requires no modification to work with pyfakefs.

Usage

See the usage tutorial for a concrete example of how to apply pyfakefs.

Usually you would use it this way:

import pyfakefs.fake_filesystem as fake_fs

# Create a faked file system
fs = fake_fs.FakeFilesystem()

# Do some setup on the faked file system
fs.CreateFile('/var/data/xx1.txt')
fs.CreateFile('/var/data/xx2.txt')

# Replace some built-in file system related modules you use with faked ones

# Assuming you are using the mock library to ... mock things
try:
    from unittest.mock import patch  # In Python 3, mock is built-in
except ImportError:
    from mock import patch  # Python 2

import pyfakefs.fake_filesystem_glob as fake_glob

# Note that this fake module is based on the fake fs you just created
glob = fake_glob.FakeGlobModule(fs)
with patch('mymodule.glob', glob):
    print(glob.glob('/var/data/xx*'))

Continuous Integration

pyfakefs is automatically tested with Python 2.6 and above, and it is currently .

See Travis-CI for test results for each Python version.

Installation

Compatibility

pyfakefs works with Python 2.6 and above. pyfakefs requires mox3.

PyPi

pyfakefs is available on PyPi.

History

pyfakefs.py was initially developed at Google by Mike Bland as a modest fake implementation of core Python modules. It was introduced to all of Google in September 2006. Since then, it has been enhanced to extend its functionality and usefulness. At Google alone, pyfakefs is used in over 2,000 Python tests.

Google released pyfakefs to the public in 2011 as Google Code project pyfakefs.

Fork jmcgeheeiv-pyfakefs added a usage tutorial, direct support for unittest and doctest.

Fork shiffdane-jmcgeheeiv-pyfakefs added further corrections.

After the shutdown of Google Code was announced, John McGehee merged all three Google Code projects together here on GitHub where an enthusiastic community actively maintains and extends pyfakefs.