i18n: Handle missing babel locale on timesince formatting

LocalDate is dropped since the right babel locale formatter can
be already retrieved by using the more reliable get_locale_formats
function which provides sane defaults to fall back to in case of
locale being missing in babel.

The leftover code after this refactoring is simple enough to be folded
into the timesince function. Also did minor refactor to get_locale_formats
in order to allow telling to retrieve a specific locale, which eases
testing specific locales formatting.

Fixes: 'UnknownLocaleError: unknown locale 'son'

pootle/i18n/dates.py

@@ -6,49 +6,12 @@
 # or later license. See the LICENSE file for a copy of the license and the
 # AUTHORS file for copyright and authorship information.
 
-import locale as system_locale
-import os
 from datetime import datetime
 
-from babel.dates import format_timedelta
 
-from django.utils import translation
-
-
-class LocalDate(object):
-
-    def __init__(self):
-        if not self.locale_code and not os.name == "nt":
-            self.set_locale()
-
-    @property
-    def default_locale(self):
-        return translation.to_locale(translation.get_language())
-
-    def set_locale(self):
-        system_locale.setlocale(
-            system_locale.LC_ALL,
-            (self.default_locale, 'UTF-8'))
-
-    @property
-    def locale_code(self):
-        return system_locale.getlocale()[0]
-
-    def format_timesince(self, timestamp, locale=None):
-        return format_timedelta(
-            datetime.now()
-            - datetime.fromtimestamp(
-                timestamp),
-            locale=(
-                locale
-                or self.locale_code
-                or self.default_locale))
-
-
-localdate = LocalDate()
+from .formatter import get_locale_formats
 
 
 def timesince(timestamp, locale=None):
-    if locale:
-        locale = translation.to_locale(locale)
-    return localdate.format_timesince(timestamp, locale=locale)
+    timedelta = datetime.now() - datetime.fromtimestamp(timestamp)
+    return get_locale_formats(locale).timedelta(timedelta, format='long')

pootle/i18n/formatter.py

@@ -15,8 +15,10 @@
 from django.utils.translation import get_language, to_locale
 
 
-def get_locale_formats():
-    for language in [get_language(), settings.LANGUAGE_CODE, 'en-us']:
+def get_locale_formats(locale=None):
+    languages = [locale] if locale else []
+    languages += [get_language(), settings.LANGUAGE_CODE, 'en-us']
+    for language in languages:
         try:
             locale = babel_core.Locale.parse(to_locale(language))
             break

tests/i18n/dates.py

@@ -6,21 +6,35 @@
 # or later license. See the LICENSE file for a copy of the license and the
 # AUTHORS file for copyright and authorship information.
 
+import pytest
 import time
 from datetime import datetime
 
 from babel.dates import format_timedelta
 
-from pootle.i18n.dates import localdate, timesince
+from pootle.i18n.dates import timesince
+from pootle.i18n.formatter import get_locale_formats
 
 
 def test_local_date_timesince(settings):
     timestamp = time.time() - 1000000
-    assert (
-        timesince(timestamp)
-        == format_timedelta(
-            datetime.now()
-            - datetime.fromtimestamp(timestamp),
-            locale=(
-                localdate.locale_code
-                or localdate.default_locale)))
+    timedelta = datetime.now() - datetime.fromtimestamp(timestamp)
+    language = str(get_locale_formats().locale)
+    assert timesince(timestamp) == format_timedelta(timedelta, locale=language)
+
+
+@pytest.mark.parametrize('language,fallback', [
+    # Normal
+    ('af', 'af'),
+    ('en-za', 'en-za'),
+    ('en-us', 'en-us'),
+    # Code from ISO 639 reserved range (cannot be used to represent a language)
+    # so we know for sure it has to fall back.
+    ('qbb', 'en-us'),
+])
+def test_local_date_timesince_wrong_locale(language, fallback):
+    timestamp = time.time() - 1000000
+    timedelta = datetime.now() - datetime.fromtimestamp(timestamp)
+    fallback_format = get_locale_formats(fallback)
+    fallback_timedelta = fallback_format.timedelta(timedelta, format='long')
+    assert timesince(timestamp, locale=language) == fallback_timedelta