Bug 776035 part 2 - Add an enhanced MockedOpen facility to mozunit.py. r=ted

This commit is contained in:
Mike Hommey 2012-07-25 07:44:08 +02:00
parent 8532a57810
commit 46137333ad
3 changed files with 141 additions and 0 deletions

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@ -161,6 +161,7 @@ PYUNITS := \
unit-buildlist.py \ unit-buildlist.py \
unit-expandlibs.py \ unit-expandlibs.py \
unit-writemozinfo.py \ unit-writemozinfo.py \
unit-mozunit.py \
$(NULL) $(NULL)
check-preqs = \ check-preqs = \

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@ -5,6 +5,8 @@
from unittest import TextTestRunner as _TestRunner, TestResult as _TestResult from unittest import TextTestRunner as _TestRunner, TestResult as _TestResult
import unittest import unittest
import inspect import inspect
from StringIO import StringIO
import os
'''Helper to make python unit tests report the way that the Mozilla '''Helper to make python unit tests report the way that the Mozilla
unit test infrastructure expects tests to report. unit test infrastructure expects tests to report.
@ -70,5 +72,68 @@ class MozTestRunner(_TestRunner):
result.printErrorList() result.printErrorList()
return result return result
class MockedFile(StringIO):
def __init__(self, context, filename, content = ''):
self.context = context
self.name = filename
StringIO.__init__(self, content)
def close(self):
self.context.files[self.name] = self.getvalue()
StringIO.close(self)
def __enter__(self):
return self
def __exit__(self, type, value, traceback):
self.close()
class MockedOpen(object):
'''
Context manager diverting the open builtin such that opening files
can open "virtual" file instances given when creating a MockedOpen.
with MockedOpen({'foo': 'foo', 'bar': 'bar'}):
f = open('foo', 'r')
will thus open the virtual file instance for the file 'foo' to f.
MockedOpen also masks writes, so that creating or replacing files
doesn't touch the file system, while subsequently opening the file
will return the recorded content.
with MockedOpen():
f = open('foo', 'w')
f.write('foo')
self.assertRaises(Exception,f.open('foo', 'r'))
'''
def __init__(self, files = {}):
self.files = {}
for name, content in files.iteritems():
self.files[os.path.abspath(name)] = content
def __call__(self, name, mode = 'r'):
absname = os.path.abspath(name)
if 'w' in mode:
file = MockedFile(self, absname)
elif absname in self.files:
file = MockedFile(self, absname, self.files[absname])
elif 'a' in mode:
file = MockedFile(self, absname, self.open(name, 'r').read())
else:
file = self.open(name, mode)
if 'a' in mode:
file.seek(0, os.SEEK_END)
return file
def __enter__(self):
import __builtin__
self.open = __builtin__.open
__builtin__.open = self
def __exit__(self, type, value, traceback):
import __builtin__
__builtin__.open = self.open
def main(*args): def main(*args):
unittest.main(testRunner=MozTestRunner(),*args) unittest.main(testRunner=MozTestRunner(),*args)

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@ -0,0 +1,75 @@
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
from __future__ import with_statement
import sys
import os
from mozunit import main, MockedOpen
import unittest
from tempfile import mkstemp
class TestMozUnit(unittest.TestCase):
def test_mocked_open(self):
# Create a temporary file on the file system.
(fd, path) = mkstemp()
with os.fdopen(fd, 'w') as file:
file.write('foobar');
with MockedOpen({'file1': 'content1',
'file2': 'content2'}):
# Check the contents of the files given at MockedOpen creation.
self.assertEqual(open('file1', 'r').read(), 'content1')
self.assertEqual(open('file2', 'r').read(), 'content2')
# Check that overwriting these files alters their content.
with open('file1', 'w') as file:
file.write('foo')
self.assertEqual(open('file1', 'r').read(), 'foo')
# ... but not until the file is closed.
file = open('file2', 'w')
file.write('bar')
self.assertEqual(open('file2', 'r').read(), 'content2')
file.close()
self.assertEqual(open('file2', 'r').read(), 'bar')
# Check that appending to a file does append
with open('file1', 'a') as file:
file.write('bar')
self.assertEqual(open('file1', 'r').read(), 'foobar')
# Opening a non-existing file ought to fail.
self.assertRaises(IOError, open, 'file3', 'r')
# Check that writing a new file does create the file.
with open('file3', 'w') as file:
file.write('baz')
self.assertEqual(open('file3', 'r').read(), 'baz')
# Check the content of the file created outside MockedOpen.
self.assertEqual(open(path, 'r').read(), 'foobar')
# Check that overwriting a file existing on the file system
# does modify its content.
with open(path, 'w') as file:
file.write('bazqux')
self.assertEqual(open(path, 'r').read(), 'bazqux')
with MockedOpen():
# Check that appending to a file existing on the file system
# does modify its content.
with open(path, 'a') as file:
file.write('bazqux')
self.assertEqual(open(path, 'r').read(), 'foobarbazqux')
# Check that the file was not actually modified on the file system.
self.assertEqual(open(path, 'r').read(), 'foobar')
os.remove(path)
# Check that the file created inside MockedOpen wasn't actually
# created.
self.assertRaises(IOError, open, 'file3', 'r')
if __name__ == "__main__":
main()