django/tests/regressiontests/file_storage/tests.py

"""
Tests for the file storage mechanism

>>> import tempfile
>>> from django.core.files.storage import FileSystemStorage
>>> from django.core.files.base import ContentFile

# Set up a unique temporary directory
>>> import os
>>> temp_dir = tempfile.mktemp()
>>> os.makedirs(temp_dir)

>>> temp_storage = FileSystemStorage(location=temp_dir)

# Standard file access options are available, and work as expected.

>>> temp_storage.exists('storage_test')
False
>>> file = temp_storage.open('storage_test', 'w')
>>> file.write('storage contents')
>>> file.close()

>>> temp_storage.exists('storage_test')
True
>>> file = temp_storage.open('storage_test', 'r')
>>> file.read()
'storage contents'
>>> file.close()

>>> temp_storage.delete('storage_test')
>>> temp_storage.exists('storage_test')
False

# Files can only be accessed if they're below the specified location.

>>> temp_storage.exists('..')
Traceback (most recent call last):
...
SuspiciousOperation: Attempted access to '..' denied.
>>> temp_storage.open('/etc/passwd')
Traceback (most recent call last):
  ...
SuspiciousOperation: Attempted access to '/etc/passwd' denied.

# Custom storage systems can be created to customize behavior

>>> class CustomStorage(FileSystemStorage):
...     def get_available_name(self, name):
...         # Append numbers to duplicate files rather than underscores, like Trac
...
...         parts = name.split('.')
...         basename, ext = parts[0], parts[1:]
...         number = 2
...
...         while self.exists(name):
...             name = '.'.join([basename, str(number)] + ext)
...             number += 1
...
...         return name
>>> custom_storage = CustomStorage(temp_dir)

>>> first = custom_storage.save('custom_storage', ContentFile('custom contents'))
>>> first
u'custom_storage'
>>> second = custom_storage.save('custom_storage', ContentFile('more contents'))
>>> second
u'custom_storage.2'

>>> custom_storage.delete(first)
>>> custom_storage.delete(second)

# Cleanup the temp dir
>>> os.rmdir(temp_dir)

"""

# Tests for a race condition on file saving (#4948).
# This is written in such a way that it'll always pass on platforms 
# without threading.

import time
from unittest import TestCase
from django.core.files.base import ContentFile
from models import temp_storage
try:
    import threading
except ImportError:
    import dummy_threading as threading

class SlowFile(ContentFile):
    def chunks(self):
        time.sleep(1)
        return super(ContentFile, self).chunks()

class FileSaveRaceConditionTest(TestCase):
    def setUp(self):
        self.thread = threading.Thread(target=self.save_file, args=['conflict'])
    
    def save_file(self, name):
        name = temp_storage.save(name, SlowFile("Data"))
    
    def test_race_condition(self):
        self.thread.start()
        name = self.save_file('conflict')
        self.thread.join()
        self.assert_(temp_storage.exists('conflict'))
        self.assert_(temp_storage.exists('conflict_'))
        temp_storage.delete('conflict')
        temp_storage.delete('conflict_')