:param prevdate: datetime object

    :param show_short_version: if it should aproximate the date and return a shorter string

    :rtype: unicode

    :returns: unicode words describing age

    """

    now = now or datetime.datetime.now()

    order = ['year', 'month', 'day', 'hour', 'minute', 'second']

    deltas = {}

    future = False

    if prevdate > now:

        now, prevdate = prevdate, now

        future = True

    if future:

        prevdate = prevdate.replace(microsecond=0)

    # Get date parts deltas

    from dateutil import relativedelta

    for part in order:

        d = relativedelta.relativedelta(now, prevdate)

        deltas[part] = getattr(d, part + 's')

    # Fix negative offsets (there is 1 second between 10:59:59 and 11:00:00,

    # not 1 hour, -59 minutes and -59 seconds)

    for num, length in [(5, 60), (4, 60), (3, 24)]:  # seconds, minutes, hours

        part = order[num]

        carry_part = order[num - 1]

        if deltas[part] < 0:

            deltas[part] += length

            deltas[carry_part] -= 1

    # Same thing for days except that the increment depends on the (variable)

    # number of days in the month

    month_lengths = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

    if deltas['day'] < 0:

        if prevdate.month == 2 and (prevdate.year % 4 == 0 and

            (prevdate.year % 100 != 0 or prevdate.year % 400 == 0)):

            deltas['day'] += 29

        else:

            deltas['day'] += month_lengths[prevdate.month - 1]

        deltas['month'] -= 1

    if deltas['month'] < 0:

        deltas['month'] += 12

        deltas['year'] -= 1

    # Format the result

    fmt_funcs = {

        'year': lambda d: ungettext(u'%d year', '%d years', d) % d,

        'month': lambda d: ungettext(u'%d month', '%d months', d) % d,

        'day': lambda d: ungettext(u'%d day', '%d days', d) % d,

        'hour': lambda d: ungettext(u'%d hour', '%d hours', d) % d,

        'minute': lambda d: ungettext(u'%d minute', '%d minutes', d) % d,

        'second': lambda d: ungettext(u'%d second', '%d seconds', d) % d,

    }

    for i, part in enumerate(order):

        value = deltas[part]

        if value == 0:

            continue

        if i < 5:

            sub_part = order[i + 1]

            sub_value = deltas[sub_part]

        else:

            sub_value = 0

        if sub_value == 0 or show_short_version:

            if future:

                return _(u'in %s') % fmt_funcs[part](value)

            else:

                return _(u'%s ago') % fmt_funcs[part](value)

        if future:

            return _(u'in %s and %s') % (fmt_funcs[part](value),

                fmt_funcs[sub_part](sub_value))

        else:

            return _(u'%s and %s ago') % (fmt_funcs[part](value),

                fmt_funcs[sub_part](sub_value))

    return _(u'just now')

def uri_filter(uri):

    """

    Removes user:password from given url string

    :param uri:

    :rtype: unicode

    :returns: filtered list of strings

    """

    if not uri:

        return ''

    proto = ''

    def test_mention_extractor(self):

        from kallithea.lib.utils2 import extract_mentioned_users

        sample = (

            "@first hi there @marcink here's my email marcin@email.com "

            "@lukaszb check @one_more22 it pls @ ttwelve @D[] @one@two@three "

            "@MARCIN    @maRCiN @2one_more22 @john please see this http://org.pl "

            "@marian.user just do it @marco-polo and next extract @marco_polo "

            "user.dot  hej ! not-needed maril@domain.org"

        )

        s = sorted([

            '2one_more22', 'first', 'marcink', 'lukaszb', 'one', 'one_more22', 'MARCIN', 'maRCiN', 'john',

            'marian.user', 'marco-polo', 'marco_polo'], key=lambda k: k.lower())

        self.assertEqual(s, extract_mentioned_users(sample))

    @parameterized.expand([

        (dict(), u'just now'),

        (dict(seconds= -1), u'1 second ago'),

        (dict(seconds= -60 * 2), u'2 minutes ago'),

        (dict(hours= -1), u'1 hour ago'),

        (dict(hours= -24), u'1 day ago'),

        (dict(hours= -24 * 5), u'5 days ago'),

        (dict(months= -1), u'1 month ago'),

        (dict(months= -1, days= -2), u'1 month and 2 days ago'),

        (dict(months= -1, days= -20), u'1 month and 19 days ago'),

        (dict(years= -1, months= -1), u'1 year and 1 month ago'),

        (dict(years= -1, months= -10), u'1 year and 10 months ago'),

        (dict(years= -2, months= -4), u'2 years and 4 months ago'),

        (dict(years= -2, months= -11), u'2 years and 11 months ago'),

        (dict(years= -3, months= -2), u'3 years and 2 months ago'),

    ])

    def test_age(self, age_args, expected):

        from kallithea.lib.utils2 import age

        from dateutil import relativedelta

        n = datetime.datetime(year=2012, month=5, day=17)

        delt = lambda *args, **kwargs: relativedelta.relativedelta(*args, **kwargs)

        self.assertEqual(age(n + delt(**age_args), now=n), expected)

    @parameterized.expand([

        (dict(), u'just now'),

        (dict(seconds= -1), u'1 second ago'),

        (dict(seconds= -60 * 2), u'2 minutes ago'),

        (dict(hours= -1), u'1 hour ago'),

        (dict(hours= -24), u'1 day ago'),

        (dict(hours= -24 * 5), u'5 days ago'),

        (dict(months= -1), u'1 month ago'),

        (dict(months= -1, days= -2), u'1 month ago'),

        (dict(months= -1, days= -20), u'1 month ago'),

        (dict(years= -2, months= -4), u'2 years ago'),

        (dict(years= -3, months= -2), u'3 years ago'),

    ])

    def test_age_short(self, age_args, expected):

        from kallithea.lib.utils2 import age

        from dateutil import relativedelta

        n = datetime.datetime(year=2012, month=5, day=17)

        delt = lambda *args, **kwargs: relativedelta.relativedelta(*args, **kwargs)

        self.assertEqual(age(n + delt(**age_args), show_short_version=True, now=n), expected)

    @parameterized.expand([

        (dict(), u'just now'),

        (dict(seconds=1), u'in 1 second'),

        (dict(seconds=60 * 2), u'in 2 minutes'),

        (dict(hours=1), u'in 1 hour'),

        (dict(hours=24), u'in 1 day'),

        (dict(hours=24 * 5), u'in 5 days'),

        (dict(months=1), u'in 1 month'),

        (dict(months=1, days=1), u'in 1 month and 1 day'),

        (dict(years=1, months=1), u'in 1 year and 1 month')

    ])

    def test_age_in_future(self, age_args, expected):

        from kallithea.lib.utils2 import age

        from dateutil import relativedelta

        n = datetime.datetime(year=2012, month=5, day=17)

        delt = lambda *args, **kwargs: relativedelta.relativedelta(*args, **kwargs)

        self.assertEqual(age(n + delt(**age_args), now=n), expected)

    def test_tag_exctrator(self):

        sample = (

            "hello pta[tag] gog [[]] [[] sda ero[or]d [me =>>< sa]"

            "[requires] [stale] [see<>=>] [see => http://url.com]"

            "[requires => url] [lang => python] [just a tag]"

            "[,d] [ => ULR ] [obsolete] [desc]]"

        )

        from kallithea.lib.helpers import desc_stylize

        res = desc_stylize(sample)

        self.assertTrue('<div class="metatag" tag="tag">tag</div>' in res)

        self.assertTrue('<div class="metatag" tag="obsolete">obsolete</div>' in res)

        self.assertTrue('<div class="metatag" tag="stale">stale</div>' in res)

        self.assertTrue('<div class="metatag" tag="lang">python</div>' in res)

        self.assertTrue('<div class="metatag" tag="requires">requires =&gt; <a href="/url">url</a></div>' in res)

        self.assertTrue('<div class="metatag" tag="tag">tag</div>' in res)

    def test_alternative_gravatar(self):

        from kallithea.lib.helpers import gravatar_url

        _md5 = lambda s: hashlib.md5(s).hexdigest()

        #mock pylons.url

        class fake_url(object):