use fallback plural if none is defined in CLDR

fixes #69

2 files changed, 11 insertions, 1 deletions

diff --git a/babel/core.py b/babel/core.py
index 56dbf55..4ada466 100644
--- a/babel/core.py
+++ b/babel/core.py
@@ -13,12 +13,14 @@ import os
 
 from babel import localedata
 from babel._compat import pickle, string_types
+from babel.plural import PluralRule
 
 __all__ = ['UnknownLocaleError', 'Locale', 'default_locale', 'negotiate_locale',
            'parse_locale']
 
 
 _global_data = None
+_default_plural_rule = PluralRule({})
 
 
 def _raise_no_data_error():
@@ -737,7 +739,7 @@ class Locale(object):
         >>> Locale('ru').plural_form(100)
         'many'
         """
-        return self._data['plural_form']
+        return self._data.get('plural_form', _default_plural_rule)
 
 
 def default_locale(category=None, aliases=LOCALE_ALIASES):
diff --git a/tests/test_plural.py b/tests/test_plural.py
index 5fe67a5..7f31fd9 100644
--- a/tests/test_plural.py
+++ b/tests/test_plural.py
@@ -90,3 +90,11 @@ def test_plural_within_rules():
     assert p(7) == 'few'
     assert p(8) == 'few'
     assert p(9) == 'few'
+
+
+def test_locales_with_no_plural_rules_have_default():
+    from babel import Locale
+    aa_plural = Locale.parse('aa').plural_form
+    assert aa_plural(1) == 'other'
+    assert aa_plural(2) == 'other'
+    assert aa_plural(15) == 'other'