~bzr-pqm/bzr/bzr.dev

# Copyright (C) 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

"""Fixtures that can be used within tests.

Fixtures can be created during a test as a way to separate out creation of

objects to test.  Fixture objects can hold some state so that different 

objects created during a test instance can be related.  Normally a fixture

should live only for the duration of a single test, and its tearDown method

should be passed to `addCleanup` on the test.

"""

import itertools

def generate_unicode_names():

    """Generate a sequence of arbitrary unique unicode names.

    By default they are not representable in ascii.

    >>> gen = generate_unicode_names()

    >>> n1 = gen.next()

    >>> n2 = gen.next()

    >>> type(n1)

    <type 'unicode'>

    >>> n1 == n2

    False

    >>> n1.encode('ascii', 'replace') == n1

    False

    """

    # include a mathematical symbol unlikely to be in 8-bit encodings

    return (u"\N{SINE WAVE}%d" % x for x in itertools.count())

interesting_encodings = [

    ('iso-8859-1', False),

    ('ascii', False),

    ('cp850', False),

    ('utf-8', True),

    ('ucs-2', True),

    ]

def generate_unicode_encodings(universal_encoding=None):

    """Return a generator of unicode encoding names.

    These can be passed to Python encode/decode/etc.

    :param universal_encoding: True/False/None tristate to say whether the

        generated encodings either can or cannot encode all unicode 

        strings.

    >>> n1 = generate_unicode_names().next()

    >>> enc = generate_unicode_encodings(universal_encoding=True).next()

    >>> enc2 = generate_unicode_encodings(universal_encoding=False).next()

    >>> n1.encode(enc).decode(enc) == n1

    True

    >>> try:

    ...   n1.encode(enc2).decode(enc2)

    ... except UnicodeError:

    ...   print 'fail'

    fail

    """

    # TODO: check they're supported on this platform?

    if universal_encoding is not None:

        e = [n for (n, u) in interesting_encodings if u == universal_encoding]

    else:

        e = [n for (n, u) in interesting_encodings]

    return itertools.cycle(iter(e))

class RecordingContextManager(object):

    """A context manager that records."""

    def __init__(self):

        self._calls = []

    def __enter__(self):

        self._calls.append('__enter__')

        return self # This is bound to the 'as' clause in a with statement.

    def __exit__(self, exc_type, exc_val, exc_tb):

        self._calls.append('__exit__')

        return False # propogate exceptions.