Use ``msgid_plural`` as ``default_plural`` if not provided in ``translate()``.

4 files changed, 68 insertions, 9 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index ea015b0..423ca47 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,7 +5,8 @@
 4.6 (unreleased)
 ================
 
-- Nothing changed yet.
+- Use ``msgid_plural`` as ``default_plural`` if not provided in
+  ``translate()``.
 
 
 4.5 (2018-10-19)
diff --git a/src/zope/i18n/__init__.py b/src/zope/i18n/__init__.py
index 5f7d775..dd525ea 100644
--- a/src/zope/i18n/__init__.py
+++ b/src/zope/i18n/__init__.py
@@ -169,6 +169,8 @@ def translate(msgid, domain=None, mapping=None, context=None,
 
     if default is None:
         default = text_type(msgid)
+    if msgid_plural is not None and default_plural is None:
+        default_plural = text_type(msgid_plural)
 
     if domain:
         util = queryUtility(ITranslationDomain, domain)
diff --git a/src/zope/i18n/tests/test_plurals.py b/src/zope/i18n/tests/test_plurals.py
index 4f7813e..12b46cc 100644
--- a/src/zope/i18n/tests/test_plurals.py
+++ b/src/zope/i18n/tests/test_plurals.py
@@ -16,10 +16,13 @@
 """
 import os
 import unittest
-from zope.i18n import tests
+
+import zope.component
+from zope.i18n import tests, translate
 from zope.i18n.translationdomain import TranslationDomain
 from zope.i18n.gettextmessagecatalog import GettextMessageCatalog
 from zope.i18nmessageid import MessageFactory
+from zope.i18n.interfaces import ITranslationDomain
 
 
 class TestPlurals(unittest.TestCase):
@@ -38,6 +41,57 @@ class TestPlurals(unittest.TestCase):
         domain.addCatalog(catalog)
         return domain
 
+    def test_defaults(self):
+        domain = self._getTranslationDomain('en')
+        zope.component.provideUtility(domain, ITranslationDomain, 'default')
+        self.assertEqual(
+            translate('One apple', domain='default',
+                      msgid_plural='%d apples', number=0),
+            '0 apples')
+        self.assertEqual(
+            translate('One apple', domain='default',
+                      msgid_plural='%d apples', number=1),
+            'One apple')
+        self.assertEqual(
+            translate('One apple', domain='default',
+                      msgid_plural='%d apples', number=2),
+            '2 apples')
+
+    def test_missing_queryPluralMessage(self):
+        catalog = self._getMessageCatalog('en')
+        self.assertEqual(catalog.language, 'en')
+
+        self.assertEqual(
+            catalog.queryPluralMessage(
+                'One apple', '%d apples', 0,
+                dft1='One fruit', dft2='%d fruits'),
+            '0 fruits')
+
+        self.assertEqual(
+            catalog.queryPluralMessage(
+                'One apple.', '%d apples.', 1,
+                dft1='One fruit', dft2='%d fruits'),
+            'One fruit')
+
+        self.assertEqual(
+            catalog.queryPluralMessage(
+                'One apple.', '%d apples.', 2,
+                dft1='One fruit', dft2='%d fruits'),
+            '2 fruits')
+
+    def test_missing_getPluralMessage(self):
+        catalog = self._getMessageCatalog('en')
+        self.assertEqual(catalog.language, 'en')
+
+        with self.assertRaises(KeyError):
+            catalog.getPluralMessage('One apple', '%d fruits', 0)
+
+        with self.assertRaises(KeyError):
+            catalog.getPluralMessage('One apple', '%d fruits', 1)
+
+        with self.assertRaises(KeyError):
+            catalog.getPluralMessage('One apple', '%d fruits', 2)
+
     def test_GermanPlurals(self):
         """Germanic languages such as english and german share the plural
         rule. We test the german here.
diff --git a/src/zope/i18n/tests/test_translationdomain.py b/src/zope/i18n/tests/test_translationdomain.py
index f206d5b..34ee21a 100644
--- a/src/zope/i18n/tests/test_translationdomain.py
+++ b/src/zope/i18n/tests/test_translationdomain.py
@@ -115,13 +115,15 @@ class TestGlobalTranslationDomain(TestITranslationDomain, unittest.TestCase):
                           translate, msgid1, None, None, 'en', "default")
         # Recusrive translations also work if the original message id wasn't a
         # message id but a unicode with a directly passed mapping
-        self.assertEqual("Color: BLUE/YELLOW",
-                         translate(u"Color: ${color1}/${color2}", mapping=mapping,
-                                   target_language='en'))
-
-        # If we have mapping with a message id from a different domain, make sure
-        # we use that domain, not ours. If the message domain is not registered yet,
-        # we should return a defualt translation.
+        self.assertEqual(
+            "Color: BLUE/YELLOW",
+            translate(u"Color: ${color1}/${color2}", mapping=mapping,
+                      target_language='en'))
+
+        # If we have mapping with a message id from a different
+        # domain, make sure we use that domain, not ours. If the
+        # message domain is not registered yet, we should return a
+        # defualt translation.
         alt_factory = MessageFactory('alt')
         msgid_sub = alt_factory(u"special", default=u"oohhh")
         mapping = {'message': msgid_sub}