/brz/remove-bazaar

# Copyright (C) 2006-2010 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""Tests for the formatting and construction of errors."""

import socket

import sys

from bzrlib import (

    bzrdir,

    errors,

    osutils,

    symbol_versioning,

    urlutils,

    )

from bzrlib.tests import TestCase, TestCaseWithTransport

class TestErrors(TestCaseWithTransport):

    def test_bad_filename_encoding(self):

        error = errors.BadFilenameEncoding('bad/filen\xe5me', 'UTF-8')

        self.assertEqualDiff(

            "Filename 'bad/filen\\xe5me' is not valid in your current"

            " filesystem encoding UTF-8",

            str(error))

    def test_corrupt_dirstate(self):

        error = errors.CorruptDirstate('path/to/dirstate', 'the reason why')

        self.assertEqualDiff(

            "Inconsistency in dirstate file path/to/dirstate.\n"

            "Error: the reason why",

            str(error))

    def test_dirstate_corrupt(self):

        error = errors.DirstateCorrupt('.bzr/checkout/dirstate',

                                       'trailing garbage: "x"')

        self.assertEqualDiff("The dirstate file (.bzr/checkout/dirstate)"

            " appears to be corrupt: trailing garbage: \"x\"",

            str(error))

    def test_disabled_method(self):

        error = errors.DisabledMethod("class name")

        self.assertEqualDiff(

            "The smart server method 'class name' is disabled.", str(error))

    def test_duplicate_file_id(self):

        error = errors.DuplicateFileId('a_file_id', 'foo')

        self.assertEqualDiff('File id {a_file_id} already exists in inventory'

                             ' as foo', str(error))

    def test_duplicate_help_prefix(self):

        error = errors.DuplicateHelpPrefix('foo')

        self.assertEqualDiff('The prefix foo is in the help search path twice.',

            str(error))

    def test_ghost_revisions_have_no_revno(self):

        error = errors.GhostRevisionsHaveNoRevno('target', 'ghost_rev')

        self.assertEqualDiff("Could not determine revno for {target} because"

                             " its ancestry shows a ghost at {ghost_rev}",

                             str(error))

    def test_incompatibleAPI(self):

        error = errors.IncompatibleAPI("module", (1, 2, 3), (4, 5, 6), (7, 8, 9))

        self.assertEqualDiff(

            'The API for "module" is not compatible with "(1, 2, 3)". '

            'It supports versions "(4, 5, 6)" to "(7, 8, 9)".',

            str(error))

    def test_inconsistent_delta(self):

        error = errors.InconsistentDelta('path', 'file-id', 'reason for foo')

        self.assertEqualDiff(

            "An inconsistent delta was supplied involving 'path', 'file-id'\n"

            "reason: reason for foo",

            str(error))

    def test_inconsistent_delta_delta(self):

        error = errors.InconsistentDeltaDelta([], 'reason')

        self.assertEqualDiff(

            "An inconsistent delta was supplied: []\nreason: reason",

            str(error))

    def test_in_process_transport(self):

        error = errors.InProcessTransport('fpp')

        self.assertEqualDiff(

            "The transport 'fpp' is only accessible within this process.",

            str(error))

    def test_invalid_http_range(self):

        error = errors.InvalidHttpRange('path',

                                        'Content-Range: potatoes 0-00/o0oo0',

                                        'bad range')

        self.assertEquals("Invalid http range"

                          " 'Content-Range: potatoes 0-00/o0oo0'"

                          " for path: bad range",

                          str(error))

    def test_invalid_range(self):

        error = errors.InvalidRange('path', 12, 'bad range')

        self.assertEquals("Invalid range access in path at 12: bad range",

                          str(error))

    def test_inventory_modified(self):

        error = errors.InventoryModified("a tree to be repred")

        self.assertEqualDiff("The current inventory for the tree 'a tree to "

            "be repred' has been modified, so a clean inventory cannot be "

            "read without data loss.",

            str(error))

    def test_jail_break(self):

        error = errors.JailBreak("some url")

        self.assertEqualDiff("An attempt to access a url outside the server"

            " jail was made: 'some url'.",

            str(error))

    def test_lock_active(self):

        error = errors.LockActive("lock description")

        self.assertEqualDiff("The lock for 'lock description' is in use and "

            "cannot be broken.",

            str(error))

    def test_lock_corrupt(self):

        error = errors.LockCorrupt("corruption info")

        self.assertEqualDiff("Lock is apparently held, but corrupted: "

            "corruption info\n"

            "Use 'bzr break-lock' to clear it",

            str(error))

    def test_knit_data_stream_incompatible(self):

        error = errors.KnitDataStreamIncompatible(

            'stream format', 'target format')

        self.assertEqual('Cannot insert knit data stream of format '

                         '"stream format" into knit of format '

                         '"target format".', str(error))

    def test_knit_data_stream_unknown(self):

        error = errors.KnitDataStreamUnknown(

            'stream format')

        self.assertEqual('Cannot parse knit data stream of format '

                         '"stream format".', str(error))

    def test_knit_header_error(self):

        error = errors.KnitHeaderError('line foo\n', 'path/to/file')

        self.assertEqual("Knit header error: 'line foo\\n' unexpected"

                         " for file \"path/to/file\".", str(error))

    def test_knit_index_unknown_method(self):

        error = errors.KnitIndexUnknownMethod('http://host/foo.kndx',

                                              ['bad', 'no-eol'])

        self.assertEqual("Knit index http://host/foo.kndx does not have a"

                         " known method in options: ['bad', 'no-eol']",

                         str(error))

    def test_medium_not_connected(self):

        error = errors.MediumNotConnected("a medium")

        self.assertEqualDiff(

            "The medium 'a medium' is not connected.", str(error))

    def test_no_public_branch(self):

        b = self.make_branch('.')

        error = errors.NoPublicBranch(b)

        url = urlutils.unescape_for_display(b.base, 'ascii')

        self.assertEqualDiff(

            'There is no public branch set for "%s".' % url, str(error))

    def test_no_repo(self):

        dir = bzrdir.BzrDir.create(self.get_url())

        error = errors.NoRepositoryPresent(dir)

        self.assertNotEqual(-1, str(error).find((dir.transport.clone('..').base)))

        self.assertEqual(-1, str(error).find((dir.transport.base)))

    def test_no_smart_medium(self):

        error = errors.NoSmartMedium("a transport")

        self.assertEqualDiff("The transport 'a transport' cannot tunnel the "

            "smart protocol.",

            str(error))

    def test_no_help_topic(self):

        error = errors.NoHelpTopic("topic")

        self.assertEqualDiff("No help could be found for 'topic'. "

            "Please use 'bzr help topics' to obtain a list of topics.",

            str(error))

    def test_no_such_id(self):

        error = errors.NoSuchId("atree", "anid")

        self.assertEqualDiff("The file id \"anid\" is not present in the tree "

            "atree.",

            str(error))

    def test_no_such_revision_in_tree(self):

        error = errors.NoSuchRevisionInTree("atree", "anid")

        self.assertEqualDiff("The revision id {anid} is not present in the"

                             " tree atree.", str(error))

        self.assertIsInstance(error, errors.NoSuchRevision)

    def test_not_stacked(self):

        error = errors.NotStacked('a branch')

        self.assertEqualDiff("The branch 'a branch' is not stacked.",

            str(error))

    def test_not_write_locked(self):

        error = errors.NotWriteLocked('a thing to repr')

        self.assertEqualDiff("'a thing to repr' is not write locked but needs "

            "to be.",

            str(error))

    def test_lock_failed(self):

        error = errors.LockFailed('http://canonical.com/', 'readonly transport')

        self.assertEqualDiff("Cannot lock http://canonical.com/: readonly transport",

            str(error))

        self.assertFalse(error.internal_error)

    def test_too_many_concurrent_requests(self):

        error = errors.TooManyConcurrentRequests("a medium")

        self.assertEqualDiff("The medium 'a medium' has reached its concurrent "

            "request limit. Be sure to finish_writing and finish_reading on "

            "the currently open request.",

            str(error))

    def test_unavailable_representation(self):

        error = errors.UnavailableRepresentation(('key',), "mpdiff", "fulltext")

        self.assertEqualDiff("The encoding 'mpdiff' is not available for key "

            "('key',) which is encoded as 'fulltext'.",

            str(error))

    def test_unknown_hook(self):

        error = errors.UnknownHook("branch", "foo")

        self.assertEqualDiff("The branch hook 'foo' is unknown in this version"

            " of bzrlib.",

            str(error))

        error = errors.UnknownHook("tree", "bar")

        self.assertEqualDiff("The tree hook 'bar' is unknown in this version"

            " of bzrlib.",

            str(error))

    def test_unstackable_branch_format(self):

        format = u'foo'

        url = "/foo"

        error = errors.UnstackableBranchFormat(format, url)

        self.assertEqualDiff(

            "The branch '/foo'(foo) is not a stackable format. "

            "You will need to upgrade the branch to permit branch stacking.",

            str(error))

    def test_unstackable_location(self):

        error = errors.UnstackableLocationError('foo', 'bar')

        self.assertEqualDiff("The branch 'foo' cannot be stacked on 'bar'.",

            str(error))

    def test_unstackable_repository_format(self):

        format = u'foo'

        url = "/foo"

        error = errors.UnstackableRepositoryFormat(format, url)

        self.assertEqualDiff(

            "The repository '/foo'(foo) is not a stackable format. "

            "You will need to upgrade the repository to permit branch stacking.",

            str(error))

    def test_up_to_date(self):

        error = errors.UpToDateFormat(bzrdir.BzrDirFormat4())

        self.assertEqualDiff("The branch format All-in-one "

                             "format 4 is already at the most "

                             "recent format.",

                             str(error))

    def test_corrupt_repository(self):

        repo = self.make_repository('.')

        error = errors.CorruptRepository(repo)

        self.assertEqualDiff("An error has been detected in the repository %s.\n"

                             "Please run bzr reconcile on this repository." %

                             repo.bzrdir.root_transport.base,

                             str(error))

    def test_read_error(self):

        # a unicode path to check that %r is being used.

        path = u'a path'

        error = errors.ReadError(path)

        self.assertEqualDiff("Error reading from u'a path'.", str(error))

    def test_bad_index_format_signature(self):

        error = errors.BadIndexFormatSignature("foo", "bar")

        self.assertEqual("foo is not an index of type bar.",

            str(error))

    def test_bad_index_data(self):

        error = errors.BadIndexData("foo")

        self.assertEqual("Error in data for index foo.",

            str(error))

    def test_bad_index_duplicate_key(self):

        error = errors.BadIndexDuplicateKey("foo", "bar")

        self.assertEqual("The key 'foo' is already in index 'bar'.",

            str(error))

    def test_bad_index_key(self):

        error = errors.BadIndexKey("foo")

        self.assertEqual("The key 'foo' is not a valid key.",

            str(error))

    def test_bad_index_options(self):

        error = errors.BadIndexOptions("foo")

        self.assertEqual("Could not parse options for index foo.",

            str(error))

    def test_bad_index_value(self):

        error = errors.BadIndexValue("foo")

        self.assertEqual("The value 'foo' is not a valid value.",

            str(error))

    def test_bzrnewerror_is_deprecated(self):

        class DeprecatedError(errors.BzrNewError):

            pass

        self.callDeprecated(['BzrNewError was deprecated in bzr 0.13; '

             'please convert DeprecatedError to use BzrError instead'],

            DeprecatedError)

    def test_bzrerror_from_literal_string(self):

        # Some code constructs BzrError from a literal string, in which case

        # no further formatting is done.  (I'm not sure raising the base class

        # is a great idea, but if the exception is not intended to be caught

        # perhaps no more is needed.)

        try:

            raise errors.BzrError('this is my errors; %d is not expanded')

        except errors.BzrError, e:

            self.assertEqual('this is my errors; %d is not expanded', str(e))

    def test_reading_completed(self):

        error = errors.ReadingCompleted("a request")

        self.assertEqualDiff("The MediumRequest 'a request' has already had "

            "finish_reading called upon it - the request has been completed and"

            " no more data may be read.",

            str(error))

    def test_writing_completed(self):

        error = errors.WritingCompleted("a request")

        self.assertEqualDiff("The MediumRequest 'a request' has already had "

            "finish_writing called upon it - accept bytes may not be called "

            "anymore.",

            str(error))

    def test_writing_not_completed(self):

        error = errors.WritingNotComplete("a request")

        self.assertEqualDiff("The MediumRequest 'a request' has not has "

            "finish_writing called upon it - until the write phase is complete"

            " no data may be read.",

            str(error))

    def test_transport_not_possible(self):

        error = errors.TransportNotPossible('readonly', 'original error')

        self.assertEqualDiff('Transport operation not possible:'

                         ' readonly original error', str(error))

    def assertSocketConnectionError(self, expected, *args, **kwargs):

        """Check the formatting of a SocketConnectionError exception"""

        e = errors.SocketConnectionError(*args, **kwargs)

        self.assertEqual(expected, str(e))

    def test_socket_connection_error(self):

        """Test the formatting of SocketConnectionError"""

        # There should be a default msg about failing to connect

        # we only require a host name.

        self.assertSocketConnectionError(

            'Failed to connect to ahost',

            'ahost')

        # If port is None, we don't put :None

        self.assertSocketConnectionError(

            'Failed to connect to ahost',

            'ahost', port=None)

        # But if port is supplied we include it

        self.assertSocketConnectionError(

            'Failed to connect to ahost:22',

            'ahost', port=22)

        # We can also supply extra information about the error

        # with or without a port

        self.assertSocketConnectionError(

            'Failed to connect to ahost:22; bogus error',

            'ahost', port=22, orig_error='bogus error')

        self.assertSocketConnectionError(

            'Failed to connect to ahost; bogus error',

            'ahost', orig_error='bogus error')

        # An exception object can be passed rather than a string

        orig_error = ValueError('bad value')

        self.assertSocketConnectionError(

            'Failed to connect to ahost; %s' % (str(orig_error),),

            host='ahost', orig_error=orig_error)

        # And we can supply a custom failure message

        self.assertSocketConnectionError(

            'Unable to connect to ssh host ahost:444; my_error',

            host='ahost', port=444, msg='Unable to connect to ssh host',

            orig_error='my_error')

    def test_target_not_branch(self):

        """Test the formatting of TargetNotBranch."""

        error = errors.TargetNotBranch('foo')

        self.assertEqual(

            "Your branch does not have all of the revisions required in "

            "order to merge this merge directive and the target "

            "location specified in the merge directive is not a branch: "

            "foo.", str(error))

    def test_malformed_bug_identifier(self):

        """Test the formatting of MalformedBugIdentifier."""

        error = errors.MalformedBugIdentifier('bogus', 'reason for bogosity')

        self.assertEqual(

            'Did not understand bug identifier bogus: reason for bogosity. '

            'See "bzr help bugs" for more information on this feature.',

            str(error))

    def test_unknown_bug_tracker_abbreviation(self):

        """Test the formatting of UnknownBugTrackerAbbreviation."""

        branch = self.make_branch('some_branch')

        error = errors.UnknownBugTrackerAbbreviation('xxx', branch)

        self.assertEqual(

            "Cannot find registered bug tracker called xxx on %s" % branch,

            str(error))

    def test_unexpected_smart_server_response(self):

        e = errors.UnexpectedSmartServerResponse(('not yes',))

        self.assertEqual(

            "Could not understand response from smart server: ('not yes',)",

            str(e))

    def test_unknown_container_format(self):

        """Test the formatting of UnknownContainerFormatError."""

        e = errors.UnknownContainerFormatError('bad format string')

        self.assertEqual(

            "Unrecognised container format: 'bad format string'",

            str(e))

    def test_unexpected_end_of_container(self):

        """Test the formatting of UnexpectedEndOfContainerError."""

        e = errors.UnexpectedEndOfContainerError()

        self.assertEqual(

            "Unexpected end of container stream", str(e))

    def test_unknown_record_type(self):

        """Test the formatting of UnknownRecordTypeError."""

        e = errors.UnknownRecordTypeError("X")

        self.assertEqual(

            "Unknown record type: 'X'",

            str(e))

    def test_invalid_record(self):

        """Test the formatting of InvalidRecordError."""

        e = errors.InvalidRecordError("xxx")

        self.assertEqual(

            "Invalid record: xxx",

            str(e))

    def test_container_has_excess_data(self):

        """Test the formatting of ContainerHasExcessDataError."""

        e = errors.ContainerHasExcessDataError("excess bytes")

        self.assertEqual(

            "Container has data after end marker: 'excess bytes'",

            str(e))

    def test_duplicate_record_name_error(self):

        """Test the formatting of DuplicateRecordNameError."""

        e = errors.DuplicateRecordNameError(u"n\xe5me".encode('utf-8'))

        self.assertEqual(

            "Container has multiple records with the same name: n\xc3\xa5me",

            str(e))

    def test_check_error(self):

        # This has a member called 'message', which is problematic in

        # python2.5 because that is a slot on the base Exception class

        e = errors.BzrCheckError('example check failure')

        self.assertEqual(

            "Internal check failed: example check failure",

            str(e))

        self.assertTrue(e.internal_error)

    def test_repository_data_stream_error(self):

        """Test the formatting of RepositoryDataStreamError."""

        e = errors.RepositoryDataStreamError(u"my reason")

        self.assertEqual(

            "Corrupt or incompatible data stream: my reason", str(e))

    def test_immortal_pending_deletion_message(self):

        err = errors.ImmortalPendingDeletion('foo')

        self.assertEquals(

            "Unable to delete transform temporary directory foo.  "

            "Please examine foo to see if it contains any files "

            "you wish to keep, and delete it when you are done.",

            str(err))

    def test_unable_create_symlink(self):

        err = errors.UnableCreateSymlink()

        self.assertEquals(

            "Unable to create symlink on this platform",

            str(err))

        err = errors.UnableCreateSymlink(path=u'foo')

        self.assertEquals(

            "Unable to create symlink 'foo' on this platform",

            str(err))

        err = errors.UnableCreateSymlink(path=u'\xb5')

        self.assertEquals(

            "Unable to create symlink u'\\xb5' on this platform",

            str(err))

    def test_invalid_url_join(self):

        """Test the formatting of InvalidURLJoin."""

        e = errors.InvalidURLJoin('Reason', 'base path', ('args',))

        self.assertEqual(

            "Invalid URL join request: Reason: 'base path' + ('args',)",

            str(e))

    def test_incorrect_url(self):

        err = errors.InvalidBugTrackerURL('foo', 'http://bug.com/')

        self.assertEquals(

            ("The URL for bug tracker \"foo\" doesn't contain {id}: "

             "http://bug.com/"),

            str(err))

    def test_unable_encode_path(self):

        err = errors.UnableEncodePath('foo', 'executable')

        self.assertEquals("Unable to encode executable path 'foo' in "

            "user encoding " + osutils.get_user_encoding(),

            str(err))

    def test_unknown_format(self):

        err = errors.UnknownFormatError('bar', kind='foo')

        self.assertEquals("Unknown foo format: 'bar'", str(err))

    def test_unknown_rules(self):

        err = errors.UnknownRules(['foo', 'bar'])

        self.assertEquals("Unknown rules detected: foo, bar.", str(err))

    def test_hook_failed(self):

        # Create an exc_info tuple by raising and catching an exception.

        try:

            1/0

        except ZeroDivisionError:

            exc_info = sys.exc_info()

        err = errors.HookFailed('hook stage', 'hook name', exc_info, warn=False)

        self.assertStartsWith(

            str(err), 'Hook \'hook name\' during hook stage failed:\n')

        self.assertEndsWith(

            str(err), 'integer division or modulo by zero')

    def test_tip_change_rejected(self):

        err = errors.TipChangeRejected(u'Unicode message\N{INTERROBANG}')

        self.assertEquals(

            u'Tip change rejected: Unicode message\N{INTERROBANG}',

            unicode(err))

        self.assertEquals(

            'Tip change rejected: Unicode message\xe2\x80\xbd',

            str(err))

    def test_error_from_smart_server(self):

        error_tuple = ('error', 'tuple')

        err = errors.ErrorFromSmartServer(error_tuple)

        self.assertEquals(

            "Error received from smart server: ('error', 'tuple')", str(err))

    def test_untranslateable_error_from_smart_server(self):

        error_tuple = ('error', 'tuple')

        orig_err = errors.ErrorFromSmartServer(error_tuple)

        err = errors.UnknownErrorFromSmartServer(orig_err)

        self.assertEquals(

            "Server sent an unexpected error: ('error', 'tuple')", str(err))

    def test_smart_message_handler_error(self):

        # Make an exc_info tuple.

        try:

            raise Exception("example error")

        except Exception:

            exc_info = sys.exc_info()

        err = errors.SmartMessageHandlerError(exc_info)

        self.assertStartsWith(

            str(err), "The message handler raised an exception:\n")

        self.assertEndsWith(str(err), "Exception: example error\n")

    def test_must_have_working_tree(self):

        err = errors.MustHaveWorkingTree('foo', 'bar')

        self.assertEqual(str(err), "Branching 'bar'(foo) must create a"

                                   " working tree.")

    def test_no_such_view(self):

        err = errors.NoSuchView('foo')

        self.assertEquals("No such view: foo.", str(err))

    def test_views_not_supported(self):

        err = errors.ViewsNotSupported('atree')

        err_str = str(err)

        self.assertStartsWith(err_str, "Views are not supported by ")

        self.assertEndsWith(err_str, "; use 'bzr upgrade' to change your "

            "tree to a later format.")

    def test_file_outside_view(self):

        err = errors.FileOutsideView('baz', ['foo', 'bar'])

        self.assertEquals('Specified file "baz" is outside the current view: '

            'foo, bar', str(err))

    def test_invalid_shelf_id(self):

        invalid_id = "foo"

        err = errors.InvalidShelfId(invalid_id)

        self.assertEqual('"foo" is not a valid shelf id, '

            'try a number instead.', str(err))

    def test_unresumable_write_group(self):

        repo = "dummy repo"

        wg_tokens = ['token']

        reason = "a reason"

        err = errors.UnresumableWriteGroup(repo, wg_tokens, reason)

        self.assertEqual(

            "Repository dummy repo cannot resume write group "

            "['token']: a reason", str(err))

    def test_unsuspendable_write_group(self):

        repo = "dummy repo"

        err = errors.UnsuspendableWriteGroup(repo)

        self.assertEqual(

            'Repository dummy repo cannot suspend a write group.', str(err))

    def test_not_branch_no_args(self):

        err = errors.NotBranchError('path')

        self.assertEqual('Not a branch: "path".', str(err))

    def test_not_branch_bzrdir_with_repo(self):

        bzrdir = self.make_repository('repo').bzrdir

        err = errors.NotBranchError('path', bzrdir=bzrdir)

        self.assertEqual(

            'Not a branch: "path": location is a repository.', str(err))

    def test_not_branch_bzrdir_without_repo(self):

        bzrdir = self.make_bzrdir('bzrdir')

        err = errors.NotBranchError('path', bzrdir=bzrdir)

        self.assertEqual('Not a branch: "path".', str(err))

    def test_not_branch_laziness(self):

        real_bzrdir = self.make_bzrdir('path')

        class FakeBzrDir(object):

            def __init__(self):

                self.calls = []

            def open_repository(self):

                self.calls.append('open_repository')

                raise errors.NoRepositoryPresent(real_bzrdir)

        fake_bzrdir = FakeBzrDir()

        err = errors.NotBranchError('path', bzrdir=fake_bzrdir)

        self.assertEqual([], fake_bzrdir.calls)

        str(err)

        self.assertEqual(['open_repository'], fake_bzrdir.calls)

        # Stringifying twice doesn't try to open a repository twice.

        str(err)

        self.assertEqual(['open_repository'], fake_bzrdir.calls)

class PassThroughError(errors.BzrError):

    _fmt = """Pass through %(foo)s and %(bar)s"""

    def __init__(self, foo, bar):

        errors.BzrError.__init__(self, foo=foo, bar=bar)

class ErrorWithBadFormat(errors.BzrError):

    _fmt = """One format specifier: %(thing)s"""

class ErrorWithNoFormat(errors.BzrError):

    """This class has a docstring but no format string."""

class TestErrorFormatting(TestCase):

    def test_always_str(self):

        e = PassThroughError(u'\xb5', 'bar')

        self.assertIsInstance(e.__str__(), str)

        # In Python str(foo) *must* return a real byte string

        # not a Unicode string. The following line would raise a

        # Unicode error, because it tries to call str() on the string

        # returned from e.__str__(), and it has non ascii characters

        s = str(e)

        self.assertEqual('Pass through \xc2\xb5 and bar', s)