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			249 lines
		
	
	
	
		
			9.2 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			249 lines
		
	
	
	
		
			9.2 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
import unittest
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import __builtin__
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import exceptions
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import warnings
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from test.test_support import run_unittest
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import os
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from platform import system as platform_system
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def ignore_message_warning():
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    """Ignore the DeprecationWarning for BaseException.message."""
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    warnings.resetwarnings()
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    warnings.filterwarnings("ignore", "BaseException.message",
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                            DeprecationWarning)
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class ExceptionClassTests(unittest.TestCase):
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    """Tests for anything relating to exception objects themselves (e.g.,
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    inheritance hierarchy)"""
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    def test_builtins_new_style(self):
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        self.assertTrue(issubclass(Exception, object))
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    def verify_instance_interface(self, ins):
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        with warnings.catch_warnings():
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            ignore_message_warning()
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            for attr in ("args", "message", "__str__", "__repr__",
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                            "__getitem__"):
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                self.assertTrue(hasattr(ins, attr),
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                        "%s missing %s attribute" %
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                            (ins.__class__.__name__, attr))
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    def test_inheritance(self):
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        # Make sure the inheritance hierarchy matches the documentation
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        exc_set = set(x for x in dir(exceptions) if not x.startswith('_'))
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        inheritance_tree = open(os.path.join(os.path.split(__file__)[0],
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                                                'exception_hierarchy.txt'))
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        try:
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            superclass_name = inheritance_tree.readline().rstrip()
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            try:
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                last_exc = getattr(__builtin__, superclass_name)
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            except AttributeError:
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                self.fail("base class %s not a built-in" % superclass_name)
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            self.assertTrue(superclass_name in exc_set)
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            exc_set.discard(superclass_name)
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            superclasses = []  # Loop will insert base exception
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            last_depth = 0
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            for exc_line in inheritance_tree:
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                exc_line = exc_line.rstrip()
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                depth = exc_line.rindex('-')
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                exc_name = exc_line[depth+2:]  # Slice past space
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                if '(' in exc_name:
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                    paren_index = exc_name.index('(')
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                    platform_name = exc_name[paren_index+1:-1]
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                    exc_name = exc_name[:paren_index-1]  # Slice off space
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                    if platform_system() != platform_name:
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                        exc_set.discard(exc_name)
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                        continue
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                if '[' in exc_name:
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                    left_bracket = exc_name.index('[')
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                    exc_name = exc_name[:left_bracket-1]  # cover space
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                try:
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                    exc = getattr(__builtin__, exc_name)
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                except AttributeError:
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                    self.fail("%s not a built-in exception" % exc_name)
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                if last_depth < depth:
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                    superclasses.append((last_depth, last_exc))
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                elif last_depth > depth:
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                    while superclasses[-1][0] >= depth:
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                        superclasses.pop()
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                self.assertTrue(issubclass(exc, superclasses[-1][1]),
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                "%s is not a subclass of %s" % (exc.__name__,
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                    superclasses[-1][1].__name__))
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                try:  # Some exceptions require arguments; just skip them
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                    self.verify_instance_interface(exc())
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                except TypeError:
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                    pass
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                self.assertTrue(exc_name in exc_set)
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                exc_set.discard(exc_name)
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                last_exc = exc
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                last_depth = depth
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        finally:
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            inheritance_tree.close()
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        self.assertEqual(len(exc_set), 0, "%s not accounted for" % exc_set)
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    interface_tests = ("length", "args", "message", "str", "unicode", "repr",
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            "indexing")
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    def interface_test_driver(self, results):
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        for test_name, (given, expected) in zip(self.interface_tests, results):
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            self.assertEqual(given, expected, "%s: %s != %s" % (test_name,
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                given, expected))
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    def test_interface_single_arg(self):
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        # Make sure interface works properly when given a single argument
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        arg = "spam"
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        exc = Exception(arg)
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        with warnings.catch_warnings():
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            ignore_message_warning()
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            results = ([len(exc.args), 1], [exc.args[0], arg],
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                    [exc.message, arg],
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                    [str(exc), str(arg)], [unicode(exc), unicode(arg)],
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                [repr(exc), exc.__class__.__name__ + repr(exc.args)], [exc[0],
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                arg])
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            self.interface_test_driver(results)
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    def test_interface_multi_arg(self):
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        # Make sure interface correct when multiple arguments given
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        arg_count = 3
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        args = tuple(range(arg_count))
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        exc = Exception(*args)
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        with warnings.catch_warnings():
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            ignore_message_warning()
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            results = ([len(exc.args), arg_count], [exc.args, args],
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                    [exc.message, ''], [str(exc), str(args)],
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                    [unicode(exc), unicode(args)],
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                    [repr(exc), exc.__class__.__name__ + repr(exc.args)],
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                    [exc[-1], args[-1]])
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            self.interface_test_driver(results)
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    def test_interface_no_arg(self):
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        # Make sure that with no args that interface is correct
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        exc = Exception()
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        with warnings.catch_warnings():
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            ignore_message_warning()
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            results = ([len(exc.args), 0], [exc.args, tuple()],
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                    [exc.message, ''],
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                    [str(exc), ''], [unicode(exc), u''],
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                    [repr(exc), exc.__class__.__name__ + '()'], [True, True])
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            self.interface_test_driver(results)
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    def test_message_deprecation(self):
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        # As of Python 2.6, BaseException.message is deprecated.
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        with warnings.catch_warnings():
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            warnings.resetwarnings()
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            warnings.filterwarnings('error')
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            try:
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                BaseException().message
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            except DeprecationWarning:
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                pass
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            else:
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                self.fail("BaseException.message not deprecated")
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class UsageTests(unittest.TestCase):
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    """Test usage of exceptions"""
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    def raise_fails(self, object_):
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        """Make sure that raising 'object_' triggers a TypeError."""
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        try:
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            raise object_
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        except TypeError:
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            return  # What is expected.
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        self.fail("TypeError expected for raising %s" % type(object_))
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    def catch_fails(self, object_):
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        """Catching 'object_' should raise a TypeError."""
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        try:
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            try:
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                raise StandardError
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            except object_:
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                pass
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        except TypeError:
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            pass
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        except StandardError:
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            self.fail("TypeError expected when catching %s" % type(object_))
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        try:
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            try:
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                raise StandardError
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            except (object_,):
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                pass
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        except TypeError:
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            return
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        except StandardError:
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            self.fail("TypeError expected when catching %s as specified in a "
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                        "tuple" % type(object_))
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    def test_raise_classic(self):
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        # Raising a classic class is okay (for now).
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        class ClassicClass:
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            pass
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        try:
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            raise ClassicClass
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        except ClassicClass:
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            pass
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        except:
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            self.fail("unable to raise classic class")
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        try:
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            raise ClassicClass()
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        except ClassicClass:
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            pass
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        except:
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            self.fail("unable to raise class class instance")
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    def test_raise_new_style_non_exception(self):
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        # You cannot raise a new-style class that does not inherit from
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        # BaseException; the ability was not possible until BaseException's
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        # introduction so no need to support new-style objects that do not
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        # inherit from it.
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        class NewStyleClass(object):
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            pass
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        self.raise_fails(NewStyleClass)
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        self.raise_fails(NewStyleClass())
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    def test_raise_string(self):
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        # Raising a string raises TypeError.
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        self.raise_fails("spam")
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    def test_catch_string(self):
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        # Catching a string should trigger a DeprecationWarning.
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        with warnings.catch_warnings():
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            warnings.resetwarnings()
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            warnings.filterwarnings("error")
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            str_exc = "spam"
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            try:
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                try:
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                    raise StandardError
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                except str_exc:
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                    pass
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            except DeprecationWarning:
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                pass
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            except StandardError:
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                self.fail("catching a string exception did not raise "
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                            "DeprecationWarning")
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            # Make sure that even if the string exception is listed in a tuple
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            # that a warning is raised.
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            try:
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                try:
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                    raise StandardError
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                except (AssertionError, str_exc):
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                    pass
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            except DeprecationWarning:
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                pass
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            except StandardError:
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                self.fail("catching a string exception specified in a tuple did "
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                            "not raise DeprecationWarning")
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def test_main():
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    run_unittest(ExceptionClassTests, UsageTests)
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if __name__ == '__main__':
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    test_main()
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