def test_suppresses(self):
"""
Any warnings emitted by a call to a function passed to
L{_collectWarnings} are not actually emitted to the warning system.
"""
output = StringIO()
self.patch(sys, 'stdout', output)
_collectWarnings(lambda x: None, warnings.warn, "text")
self.assertEqual(output.getvalue(), "")
def test_callsObserver(self):
"""
L{_collectWarnings} calls the observer with each emitted warning.
"""
firstMessage = "dummy calls observer warning"
secondMessage = firstMessage[::-1]
events = []
def f():
events.append('call')
warnings.warn(firstMessage)
warnings.warn(secondMessage)
events.append('returning')
_collectWarnings(events.append, f)
self.assertEqual(events[0], 'call')
self.assertEqual(events[1].message, firstMessage)
self.assertEqual(events[2].message, secondMessage)
self.assertEqual(events[3], 'returning')
self.assertEqual(len(events), 4)
def test_duplicateWarningCollected(self):
"""
Subsequent emissions of a warning from a particular source site can be
collected by L{_collectWarnings}. In particular, the per-module
emitted-warning cache should be bypassed (I{__warningregistry__}).
"""
# Make sure the worst case is tested: if __warningregistry__ isn't in a
# module's globals, then the warning system will add it and start using
# it to avoid emitting duplicate warnings. Delete __warningregistry__
# to ensure that even modules which are first imported as a test is
# running still interact properly with the warning system.
global __warningregistry__
del __warningregistry__
def f():
warnings.warn("foo")
warnings.simplefilter('default')
f()
events = []
_collectWarnings(events.append, f)
self.assertEqual(len(events), 1)
self.assertEqual(events[0].message, "foo")
self.assertEqual(len(self.flushWarnings()), 1)
def test_callsFunction(self):
"""
L{_collectWarnings} returns the result of calling the callable passed to
it with the parameters given.
"""
arguments = []
value = object()
def f(*args, **kwargs):
arguments.append((args, kwargs))
return value
result = _collectWarnings(lambda x: None, f, 1, 'a', b=2, c='d')
self.assertEqual(arguments, [((1, 'a'), {'b': 2, 'c': 'd'})])
self.assertIdentical(result, value)
def test_callsObserver(self):
"""
L{_collectWarnings} calls the observer with each emitted warning.
"""
firstMessage = "dummy calls observer warning"
secondMessage = firstMessage[::-1]
thirdMessage = Warning(1, 2, 3)
events = []
def f():
events.append("call")
warnings.warn(firstMessage)
warnings.warn(secondMessage)
warnings.warn(thirdMessage)
events.append("returning")
_collectWarnings(events.append, f)
self.assertEqual(events[0], "call")
self.assertEqual(events[1].message, firstMessage)
self.assertEqual(events[2].message, secondMessage)
self.assertEqual(events[3].message, str(thirdMessage))
self.assertEqual(events[4], "returning")
self.assertEqual(len(events), 5)