pytest-tmpfs

A pytest plugin that helps you on using a temporary filesystem for testing

import json

def readjson(path: str) -> dict:
  """
  Example:
    >>> path = fs.write('a/b/c.json', '{"a": 2}')
    >>> readjson(path)
    {'a': 2}
  """
  with open(path, 'r') as f:
    return json.load(f)

This plugin is a fake filesystem manager implementation that relies on the pytest's tmp_path fixture to enable safe testing of projects that require disk operations and are difficult to mock.

Alternatives

• pyfakefs: good alternative if you wish to mock filesystem operations.
• tempfile: creates files and directories temporarily.

Install

For installing this package, just type the command below in your terminal:

pip install pytest-tmpfs

Usage

As a fixture

You can use the TmpFs as a fixture by passing tmpfs as an argument of your test function.

import pytest_tmpfs

def test_readjson(tmpfs: pytest_tmpfs.TmpFs):
    path = tmpfs.write('a/b/d.json', '{"a": 2}')
    assert readjson(path) == {'a': 2}

In doctests

By installing this plugin, all doctests are automatically enabled to use fs, a variable that stores an instance of TmpFs.

def fscheck(path: str) -> dict:
  """
  Example:
    >>> fs.touch('a/b/c.txt')
    >>> fs.ls('a/b')
    ['c.txt']
  """
  pass

Your own instance

If you seek to use this plugin without pointing to tmp_path it is possible to create your own instance and to manipulate it the way you want.

import pytest_tmpfs

def test_random():
  mypath = pathlib.Path('a/b/c')
  fs = TmpFs(mypath)

Features

The following table contains all methods that TmpFs implements and its descriptions:

Note: tmp_cwd and cwd can be used with with statements.

Contributing

Feel free to contribute to this project, just remember to use pre-commit and to write unit tests for new features/bugs.