906569de24
build's "undetected error" problems were originally detected with extension types, but we can whitebox test the same situations with new-style classes.
145 lines
4.7 KiB
Python
145 lines
4.7 KiB
Python
# Tests some corner cases with isinstance() and issubclass(). While these
|
||
# tests use new style classes and properties, they actually do whitebox
|
||
# testing of error conditions uncovered when using extension types.
|
||
|
||
import unittest
|
||
import test_support
|
||
|
||
|
||
|
||
class TestIsInstanceWhitebox(unittest.TestCase):
|
||
# Test to make sure that an AttributeError when accessing the instance's
|
||
# class's bases is masked. This was actually a bug in Python 2.2 and
|
||
# 2.2.1 where the exception wasn't caught but it also wasn't being cleared
|
||
# (leading to an "undetected error" in the debug build). Set up is,
|
||
# isinstance(inst, cls) where:
|
||
#
|
||
# - inst isn't an InstanceType
|
||
# - cls isn't a ClassType, a TypeType, or a TupleType
|
||
# - cls has a __bases__ attribute
|
||
# - inst has a __class__ attribute
|
||
# - inst.__class__ as no __bases__ attribute
|
||
#
|
||
# Sounds complicated, I know, but this mimics a situation where an
|
||
# extension type raises an AttributeError when its __bases__ attribute is
|
||
# gotten. In that case, isinstance() should return False.
|
||
def test_class_has_no_bases(self):
|
||
class I(object):
|
||
def getclass(self):
|
||
# This must return an object that has no __bases__ attribute
|
||
return None
|
||
__class__ = property(getclass)
|
||
|
||
class C(object):
|
||
def getbases(self):
|
||
return ()
|
||
__bases__ = property(getbases)
|
||
|
||
self.assertEqual(False, isinstance(I(), C()))
|
||
|
||
# Like above except that inst.__class__.__bases__ raises an exception
|
||
# other than AttributeError
|
||
def test_bases_raises_other_than_attribute_error(self):
|
||
class E(object):
|
||
def getbases(self):
|
||
raise RuntimeError
|
||
__bases__ = property(getbases)
|
||
|
||
class I(object):
|
||
def getclass(self):
|
||
return E()
|
||
__class__ = property(getclass)
|
||
|
||
class C(object):
|
||
def getbases(self):
|
||
return ()
|
||
__bases__ = property(getbases)
|
||
|
||
self.assertRaises(RuntimeError, isinstance, I(), C())
|
||
|
||
# Here's a situation where getattr(cls, '__bases__') raises an exception.
|
||
# If that exception is not AttributeError, it should not get masked
|
||
def test_dont_mask_non_attribute_error(self):
|
||
class I: pass
|
||
|
||
class C(object):
|
||
def getbases(self):
|
||
raise RuntimeError
|
||
__bases__ = property(getbases)
|
||
|
||
self.assertRaises(RuntimeError, isinstance, I(), C())
|
||
|
||
# Like above, except that getattr(cls, '__bases__') raises an
|
||
# AttributeError, which /should/ get masked as a TypeError
|
||
def test_mask_attribute_error(self):
|
||
class I: pass
|
||
|
||
class C(object):
|
||
def getbases(self):
|
||
raise AttributeError
|
||
__bases__ = property(getbases)
|
||
|
||
self.assertRaises(TypeError, isinstance, I(), C())
|
||
|
||
|
||
|
||
# These tests are similar to above, but tickle certain code paths in
|
||
# issubclass() instead of isinstance() -- really PyObject_IsSubclass()
|
||
# vs. PyObject_IsInstance().
|
||
class TestIsSubclassWhitebox(unittest.TestCase):
|
||
def test_dont_mask_non_attribute_error(self):
|
||
class C(object):
|
||
def getbases(self):
|
||
raise RuntimeError
|
||
__bases__ = property(getbases)
|
||
|
||
class S(C): pass
|
||
|
||
self.assertRaises(RuntimeError, issubclass, C(), S())
|
||
|
||
def test_mask_attribute_error(self):
|
||
class C(object):
|
||
def getbases(self):
|
||
raise AttributeError
|
||
__bases__ = property(getbases)
|
||
|
||
class S(C): pass
|
||
|
||
self.assertRaises(TypeError, issubclass, C(), S())
|
||
|
||
# Like above, but test the second branch, where the __bases__ of the
|
||
# second arg (the cls arg) is tested. This means the first arg must
|
||
# return a valid __bases__, and it's okay for it to be a normal --
|
||
# unrelated by inheritance -- class.
|
||
def test_dont_mask_non_attribute_error_in_cls_arg(self):
|
||
class B: pass
|
||
|
||
class C(object):
|
||
def getbases(self):
|
||
raise RuntimeError
|
||
__bases__ = property(getbases)
|
||
|
||
self.assertRaises(RuntimeError, issubclass, B, C())
|
||
|
||
def test_mask_attribute_error_in_cls_arg(self):
|
||
class B: pass
|
||
|
||
class C(object):
|
||
def getbases(self):
|
||
raise AttributeError
|
||
__bases__ = property(getbases)
|
||
|
||
self.assertRaises(TypeError, issubclass, B, C())
|
||
|
||
|
||
|
||
def test_main():
|
||
suite = unittest.TestSuite()
|
||
suite.addTest(unittest.makeSuite(TestIsInstanceWhitebox))
|
||
suite.addTest(unittest.makeSuite(TestIsSubclassWhitebox))
|
||
test_support.run_suite(suite)
|
||
|
||
|
||
if __name__ == '__main__':
|
||
test_main()
|