mockfs – A simple mock filesystem for unit tests¶

Example Unit Test¶

import os
import unittest

import mockfs

class ExampleTestCase(unittest.TestCase):
    def setUp(self):
        self.mfs = mockfs.replace_builtins()
        self.mfs.add_entries({'/usr/bin/mockfs-magic': 'magic'})

    def tearDown(self):
        mockfs.restore_builtins()

    def test_using_os_path(self):
        self.assertEqual(os.listdir('/usr/bin'), ['mockfs-magic'])

    def test_using_open(self):
        fh = open('/usr/bin/mockfs-magic')
        content = fh.read()
        fh.close()
        self.assertEqual(data, 'magic')

Currently supported functions:

• __builtins__.open()
• __builtins__.close()
• glob.glob()
• os.chdir()
• os.getcwd()
• os.getcwdu()
• os.listdir()
• os.makedirs()
• os.path.abspath()
• os.path.exists()
• os.path.getsize()
• os.path.islink()
• os.path.isdir()
• os.path.isfile()
• os.remove()
• os.rmdir()
• os.unlink()
• os.walk()
• shutil.rmtree()

mockfs.replace_builtins(entries=None)¶

Replace builtin functions with mockfs.

Parameters:	entries – Dictionary mapping paths to content
Returns:	Newly installed mockfs.MockFS handler

>>> import os
>>> import mockfs
>>> fs = mockfs.replace_builtins()
>>> fs.add_entries({
...         '/bin/sh': 'contents',
...         '/bin/ls': 'contents',
... })
>>> assert(os.listdir('/bin') == ['ls', 'sh'])
>>> mockfs.restore_builtins()

mockfs.restore_builtins()¶

Restore the original builtin functions.

Developer Documentation¶

Indices and tables¶

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