Files
edx-platform/common/test/utils.py

161 lines
5.0 KiB
Python

"""
General testing utilities.
"""
import functools
import sys
from contextlib import contextmanager
import pytest # lint-amnesty, pylint: disable=unused-import
from django.dispatch import Signal
from markupsafe import escape
from mock import Mock, patch
@contextmanager
def nostderr():
"""
ContextManager to suppress stderr messages
http://stackoverflow.com/a/1810086/882918
"""
savestderr = sys.stderr
class Devnull(object):
""" /dev/null incarnation as output-stream-like object """
def write(self, _):
""" Write method - just does nothing"""
pass # lint-amnesty, pylint: disable=unnecessary-pass
sys.stderr = Devnull()
try:
yield
finally:
sys.stderr = savestderr
class XssTestMixin(object):
"""
Mixin for testing XSS vulnerabilities.
"""
def assert_no_xss(self, response, xss_content):
"""Assert that `xss_content` is not present in the content of
`response`, and that its escaped version is present. Uses the
same `markupsafe.escape` function as Mako templates.
Args:
response (Response): The HTTP response
xss_content (str): The Javascript code to check for.
Returns:
None
"""
self.assertContains(response, escape(xss_content))
self.assertNotContains(response, xss_content)
def disable_signal(module, signal):
"""Replace `signal` inside of `module` with a dummy signal. Can be
used as a method or class decorator, as well as a context manager."""
return patch.object(module, signal, new=Signal())
class MockSignalHandlerMixin(object):
"""Mixin for testing sending of signals."""
@contextmanager
def assert_signal_sent(self, module, signal, *args, **kwargs):
"""Assert that a signal was sent with the correct arguments. Since
Django calls signal handlers with the signal as an argument,
it is added to `kwargs`.
Uses `mock.patch.object`, which requires the target to be
specified as a module along with a variable name inside that
module.
Args:
module (module): The module in which to patch the given signal name.
signal (str): The name of the signal to patch.
*args, **kwargs: The arguments which should have been passed
along with the signal. If `exclude_args` is passed as a
keyword argument, its value should be a list of keyword
arguments passed to the signal whose values should be
ignored.
"""
with patch.object(module, signal, new=Signal()) as mock_signal:
def handler(*args, **kwargs): # pylint: disable=unused-argument
"""No-op signal handler."""
pass # lint-amnesty, pylint: disable=unnecessary-pass
mock_handler = Mock(spec=handler)
mock_signal.connect(mock_handler)
yield
assert mock_handler.called
mock_args, mock_kwargs = mock_handler.call_args
if 'exclude_args' in kwargs:
for key in kwargs['exclude_args']:
assert key in mock_kwargs
del mock_kwargs[key]
del kwargs['exclude_args']
assert mock_args == args
assert mock_kwargs == dict(kwargs, signal=mock_signal)
@contextmanager
def skip_signal(signal, **kwargs):
"""
ContextManager to skip a signal by disconnecting it, yielding,
and then reconnecting the signal.
"""
signal.disconnect(**kwargs)
try:
yield
finally:
signal.connect(**kwargs)
class MockS3BotoMixin(object):
"""
TestCase mixin that mocks the S3BotoStorage save method and s3 connection.
"""
def setUp(self):
super(MockS3BotoMixin, self).setUp() # lint-amnesty, pylint: disable=super-with-arguments
self._mocked_connection = patch('boto.connect_s3', return_value=Mock())
self.mocked_connection = self._mocked_connection.start()
self.patcher = patch('storages.backends.s3boto.S3BotoStorage.save')
self.patcher.start()
def tearDown(self):
self._mocked_connection.stop()
self.patcher.stop()
super(MockS3BotoMixin, self).tearDown() # lint-amnesty, pylint: disable=super-with-arguments
class reprwrapper(object):
"""
Wrapper class for functions that need a normalized string representation.
"""
def __init__(self, func):
self._func = func
self.repr = u'Func: {}'.format(func.__name__)
functools.update_wrapper(self, func)
def __call__(self, *args, **kw):
return self._func(*args, **kw)
def __repr__(self):
return self.repr
def normalize_repr(func):
"""
Function decorator used to normalize its string representation.
Used to wrap functions used as ddt parameters, so pytest-xdist
doesn't complain about the sequence of discovered tests differing
between worker processes.
"""
return reprwrapper(func)