cpython/Lib/test/test_exceptions.py

# Python test set -- part 5, built-in exceptions

from test.test_support import TESTFN, unlink, run_unittest
import warnings
import sys, traceback, os
import unittest

# XXX This is not really enough, each *operation* should be tested!

class ExceptionTests(unittest.TestCase):

    def testReload(self):
        # Reloading the built-in exceptions module failed prior to Py2.2, while it
        # should act the same as reloading built-in sys.
        try:
            import exceptions
            reload(exceptions)
        except ImportError, e:
            self.fail("reloading exceptions: %s" % e)

    def raise_catch(self, exc, excname):
        try:
            raise exc, "spam"
        except exc, err:
            buf1 = str(err)
        try:
            raise exc("spam")
        except exc, err:
            buf2 = str(err)
        self.assertEquals(buf1, buf2)
        self.assertEquals(exc.__name__, excname)

    def testRaising(self):
        self.raise_catch(AttributeError, "AttributeError")
        self.assertRaises(AttributeError, getattr, sys, "undefined_attribute")

        self.raise_catch(EOFError, "EOFError")
        fp = open(TESTFN, 'w')
        fp.close()
        fp = open(TESTFN, 'r')
        savestdin = sys.stdin
        try:
            try:
                sys.stdin = fp
                x = raw_input()
            except EOFError:
                pass
        finally:
            sys.stdin = savestdin
            fp.close()
            unlink(TESTFN)

        self.raise_catch(IOError, "IOError")
        self.assertRaises(IOError, open, 'this file does not exist', 'r')

        self.raise_catch(ImportError, "ImportError")
        self.assertRaises(ImportError, __import__, "undefined_module")

        self.raise_catch(IndexError, "IndexError")
        x = []
        self.assertRaises(IndexError, x.__getitem__, 10)

        self.raise_catch(KeyError, "KeyError")
        x = {}
        self.assertRaises(KeyError, x.__getitem__, 'key')

        self.raise_catch(KeyboardInterrupt, "KeyboardInterrupt")

        self.raise_catch(MemoryError, "MemoryError")

        self.raise_catch(NameError, "NameError")
        try: x = undefined_variable
        except NameError: pass

        self.raise_catch(OverflowError, "OverflowError")
        x = 1
        for dummy in range(128):
            x += x  # this simply shouldn't blow up

        self.raise_catch(RuntimeError, "RuntimeError")

        self.raise_catch(SyntaxError, "SyntaxError")
        try: exec '/\n'
        except SyntaxError: pass

        self.raise_catch(IndentationError, "IndentationError")

        self.raise_catch(TabError, "TabError")
        # can only be tested under -tt, and is the only test for -tt
        #try: compile("try:\n\t1/0\n    \t1/0\nfinally:\n pass\n", '<string>', 'exec')
        #except TabError: pass
        #else: self.fail("TabError not raised")

        self.raise_catch(SystemError, "SystemError")

        self.raise_catch(SystemExit, "SystemExit")
        self.assertRaises(SystemExit, sys.exit, 0)

        self.raise_catch(TypeError, "TypeError")
        try: [] + ()
        except TypeError: pass

        self.raise_catch(ValueError, "ValueError")
        self.assertRaises(ValueError, chr, 10000)

        self.raise_catch(ZeroDivisionError, "ZeroDivisionError")
        try: x = 1/0
        except ZeroDivisionError: pass

        self.raise_catch(Exception, "Exception")
        try: x = 1/0
        except Exception, e: pass

    def testSyntaxErrorMessage(self):
        """make sure the right exception message is raised for each of
           these code fragments"""

        def ckmsg(src, msg):
            try:
                compile(src, '<fragment>', 'exec')
            except SyntaxError, e:
                if e.msg != msg:
                    self.fail("expected %s, got %s" % (msg, e.msg))
            else:
                self.fail("failed to get expected SyntaxError")

        s = '''while 1:
            try:
                pass
            finally:
                continue'''

        if not sys.platform.startswith('java'):
            ckmsg(s, "'continue' not supported inside 'finally' clause")

        s = '''if 1:
        try:
            continue
        except:
            pass'''

        ckmsg(s, "'continue' not properly in loop")
        ckmsg("continue\n", "'continue' not properly in loop")

    def testSettingException(self):
        """test that setting an exception at the C level works even if the
           exception object can't be constructed."""

        class BadException:
            def __init__(self_):
                raise RuntimeError, "can't instantiate BadException"

        def test_capi1():
            import _testcapi
            try:
                _testcapi.raise_exception(BadException, 1)
            except TypeError, err:
                exc, err, tb = sys.exc_info()
                co = tb.tb_frame.f_code
                self.assertEquals(co.co_name, "test_capi1")
                self.assert_(co.co_filename.endswith('test_exceptions'+os.extsep+'py'))
            else:
                self.fail("Expected exception")

        def test_capi2():
            import _testcapi
            try:
                _testcapi.raise_exception(BadException, 0)
            except RuntimeError, err:
                exc, err, tb = sys.exc_info()
                co = tb.tb_frame.f_code
                self.assertEquals(co.co_name, "__init__")
                self.assert_(co.co_filename.endswith('test_exceptions'+os.extsep+'py'))
                co2 = tb.tb_frame.f_back.f_code
                self.assertEquals(co2.co_name, "test_capi2")
            else:
                self.fail("Expected exception")

        if not sys.platform.startswith('java'):
            test_capi1()
            test_capi2()

    def testAttributes(self):
        """test that exception attributes are happy."""
        try: str(u'Hello \u00E1')
        except Exception, e: sampleUnicodeEncodeError = e

        try: unicode('\xff')
        except Exception, e: sampleUnicodeDecodeError = e

        exceptionList = [
                ( BaseException, (), { 'message' : '', 'args' : () }),
                ( BaseException, (1, ), { 'message' : 1, 'args' : ( 1, ) }),
                ( BaseException, ('foo', ), { 'message' : 'foo', 'args' : ( 'foo', ) }),
                ( BaseException, ('foo', 1), { 'message' : '', 'args' : ( 'foo', 1 ) }),
                ( SystemExit, ('foo',), { 'message' : 'foo', 'args' : ( 'foo', ),
                        'code' : 'foo' }),
                ( IOError, ('foo',), { 'message' : 'foo', 'args' : ( 'foo', ), }),
                ( IOError, ('foo', 'bar'), { 'message' : '',
                        'args' : ('foo', 'bar'), }),
                ( IOError, ('foo', 'bar', 'baz'),
                         { 'message' : '', 'args' : ('foo', 'bar'), }),
                ( EnvironmentError, ('errnoStr', 'strErrorStr', 'filenameStr'),
                        { 'message' : '', 'args' : ('errnoStr', 'strErrorStr'),
                            'strerror' : 'strErrorStr',
                            'errno' : 'errnoStr', 'filename' : 'filenameStr' }),
                ( EnvironmentError, (1, 'strErrorStr', 'filenameStr'),
                        { 'message' : '', 'args' : (1, 'strErrorStr'),
                            'strerror' : 'strErrorStr', 'errno' : 1,
                            'filename' : 'filenameStr' }),
                ( SyntaxError, ('msgStr',),
                        { 'message' : 'msgStr', 'args' : ('msgStr', ),
                            'print_file_and_line' : None, 'msg' : 'msgStr',
                            'filename' : None, 'lineno' : None, 'offset' : None,
                            'text' : None }),
                ( SyntaxError, ('msgStr', ('filenameStr', 'linenoStr', 'offsetStr',
                                'textStr')),
                        { 'message' : '', 'args' : ('msgStr', ('filenameStr',
                                'linenoStr', 'offsetStr', 'textStr' )),
                            'print_file_and_line' : None, 'msg' : 'msgStr',
                            'filename' : 'filenameStr', 'lineno' : 'linenoStr',
                            'offset' : 'offsetStr', 'text' : 'textStr' }),
                ( SyntaxError, ('msgStr', 'filenameStr', 'linenoStr', 'offsetStr',
                            'textStr', 'print_file_and_lineStr'),
                        { 'message' : '', 'args' : ('msgStr', 'filenameStr',
                                'linenoStr', 'offsetStr', 'textStr',
                                'print_file_and_lineStr'),
                            'print_file_and_line' : None, 'msg' : 'msgStr',
                            'filename' : None, 'lineno' : None, 'offset' : None,
                            'text' : None }),
                ( UnicodeError, (),
                        { 'message' : '', 'args' : (), }),
                ( sampleUnicodeEncodeError,
                        { 'message' : '', 'args' : ('ascii', u'Hello \xe1', 6, 7,
                                'ordinal not in range(128)'),
                            'encoding' : 'ascii', 'object' : u'Hello \xe1',
                            'start' : 6, 'reason' : 'ordinal not in range(128)' }),
                ( sampleUnicodeDecodeError,
                        { 'message' : '', 'args' : ('ascii', '\xff', 0, 1,
                                'ordinal not in range(128)'),
                            'encoding' : 'ascii', 'object' : '\xff',
                            'start' : 0, 'reason' : 'ordinal not in range(128)' }),
                ( UnicodeTranslateError, (u"\u3042", 0, 1, "ouch"),
                        { 'message' : '', 'args' : (u'\u3042', 0, 1, 'ouch'),
                            'object' : u'\u3042', 'reason' : 'ouch',
                            'start' : 0, 'end' : 1 }),
                ]
        try:
            exceptionList.append(
                    ( WindowsError, (1, 'strErrorStr', 'filenameStr'),
                            { 'message' : '', 'args' : (1, 'strErrorStr'),
                                'strerror' : 'strErrorStr',
                                'errno' : 22, 'filename' : 'filenameStr',
                                'winerror' : 1 }))
        except NameError: pass

        import pickle, random

        for args in exceptionList:
            expected = args[-1]
            try:
                if len(args) == 2: raise args[0]
                else: raise apply(args[0], args[1])
            except BaseException, e:
                for checkArgName in expected.keys():
                    self.assertEquals(repr(getattr(e, checkArgName)),
                                      repr(expected[checkArgName]),
                                      'exception "%s", attribute "%s"' %
                                       (repr(e), checkArgName))

                # test for pickling support
                new = pickle.loads(pickle.dumps(e, random.randint(0, 2)))
                for checkArgName in expected.keys():
                    self.assertEquals(repr(getattr(e, checkArgName)),
                                      repr(expected[checkArgName]),
                                      'pickled exception "%s", attribute "%s' %
                                      (repr(e), checkArgName))

    def testKeywordArgs(self):
        """test that builtin exception don't take keyword args,
           but user-defined subclasses can if they want"""
        self.assertRaises(TypeError, BaseException, a=1)
        class DerivedException(BaseException):
            def __init__(self, fancy_arg):
                BaseException.__init__(self)
                self.fancy_arg = fancy_arg

        x = DerivedException(fancy_arg=42)
        self.assertEquals(x.fancy_arg, 42)

def test_main():
    run_unittest(ExceptionTests)

if __name__ == '__main__':
    test_main()