Fallback to no-context translation internally, add gettext imports in…

… sample application, remove mocks from tests

Closes #6

README.md

@@ -51,32 +51,19 @@ OK, but let's say we miss a context translation:
     msgid "user"
     msgstr ""  # <-- missing translation
 
-``AttributiveTranslation`` class without fallback by default falls back context
-translation to original English string:
+``AttributiveTranslation`` class by default falls back to no-context
+translation of the original English string:
 
     >>> user = AttributiveTranslations(…).gettext('user')
     >>> 'Wybierz {.accusative} do zmiany'.format(user)
-    'Wybierz user do zmiany'
-
-``NoContextFallbackTranslations`` class makes us fall back to no-context
-translation, which may be more desirable in our use case:
-
-    >>> translations = AttributiveTranslations(…)
-    >>> translations.add_fallback(NoContextFallbackTranslations(…))
-    >>> user = translations.gettext('user')
-    >>> 'Wybierz {.accusative} do zmiany'.format(user)
     'Wybierz użytkownik do zmiany'
 
 ### Example installation
 
     from gettext import translation
     from translations import AttributiveTranslations
-    from translations import NoContextFallbackTranslations
 
     pl = translation('messages', 'locale', ['pl'], AttributiveTranslations)
-    pl.add_fallback(
-        translation('messages', 'locale', ['pl'], NoContextFallbackTranslations)
-    )
     pl.install(('pgettext',))
 
 ### Example usage

messages.po

@@ -1,40 +1,24 @@
-# SOME DESCRIPTIVE TITLE.
-# Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
-# This file is distributed under the same license as the PACKAGE package.
-# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
-#
-#, fuzzy
 msgid ""
-msgstr ""
-"Project-Id-Version: PACKAGE VERSION\n"
-"Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2020-04-20 20:14+0200\n"
-"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
-"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
-"Language-Team: LANGUAGE <LL@li.org>\n"
-"Language: \n"
-"MIME-Version: 1.0\n"
-"Content-Type: text/plain; charset=UTF-8\n"
-"Content-Transfer-Encoding: 8bit\n"
+msgstr "Content-Type: charset=UTF-8"
 
-#: sample_application.py:12
+#: sample_application.py:8
 msgid "user"
 msgstr "użytkownik"
 
-#: sample_application.py:13
+#: sample_application.py:9
 msgctxt "accusative"
 msgid "user"
 msgstr "użytkownika"
 
-#: sample_application.py:15
+#: sample_application.py:11
 msgid "group"
 msgstr "grupa"
 
-#: sample_application.py:16
+#: sample_application.py:12
 msgctxt "accusative"
 msgid "group"
 msgstr "grupę"
 
-#: sample_application.py:21
+#: sample_application.py:17
 msgid "Select {} to change"
-msgstr "Wybierz {.accusative} to change"
+msgstr "Wybierz {.accusative} do zmiany"

sample_application.py

@@ -1,11 +1,7 @@
-from gettext import translation
+from gettext import translation, gettext as _, pgettext
 from translations import AttributiveTranslations
-from translations import NoContextFallbackTranslations
 
 pl = translation('messages', 'locale', ['pl'], AttributiveTranslations)
-pl.add_fallback(
-    translation('messages', 'locale', ['pl'], NoContextFallbackTranslations)
-)
 pl.install(('pgettext',))
 
 
@@ -23,8 +19,8 @@
 
 # translation cycle:
 # make changes
-# run ``xgettext sample_application.py --keyword=pgettext:1c,2`` to regenerate PO file
-# specify UTF-8 charset by replacing CHARSET text
+# run ``xgettext sample_application.py --keyword=pgettext:1c,2 --omit-header`` to regenerate PO file
+# specify UTF-8 charset by adding empty msgid with msgstr equal to "Content-Type: charset=UTF-8"
 # translate the file
 # run ``msgfmt messages.po --output locale/pl/LC_MESSAGES/messages.mo`` to compile translation into proper location
 # run localized application

tests.py

@@ -1,10 +1,8 @@
 from collections import UserString
 from io import BytesIO
 from unittest import TestCase
-from unittest.mock import Mock
 
 from translations import AttributiveTranslations
-from translations import NoContextFallbackTranslations
 
 empty_mo_file = BytesIO(b'\x95\x04\x12\xde'  # magic number, same as gettext.GNUTranslations.LE_MAGIC.to_bytes(4, 'big')
                         b'\x00\x00\x00\x01'  # version
@@ -20,19 +18,15 @@ def test_value_returned_is_userstring(self):
 
     def test_is_attributive(self):
         t = AttributiveTranslations()
-        t.pgettext = Mock()
-        t._catalog = {}
+        t._catalog = {'attribute\x04foo': 'bar'}
 
         foo = t.gettext('foo')
-        foo.attribute
-
-        t.pgettext.assert_called_once_with('attribute', 'foo')
+        self.assertEqual('bar', foo.attribute)
 
     def test_fallbacks(self):
-        t = NoContextFallbackTranslations()
-        t.gettext = Mock()
-        t._catalog = {}
-
-        t.pgettext('samplecontext', 'samplemessage')
+        t = AttributiveTranslations()
+        t._catalog = {'user': 'użytkownik'}
 
-        t.gettext.assert_called_once_with('samplemessage')
+        message = t.gettext('user')
+        result = message.samplecontext
+        self.assertEqual('użytkownik', result)

translations.py

@@ -5,19 +5,17 @@
 class AttributiveTranslations(GNUTranslations):
     def gettext(self, message):
         gettext = super().gettext
-        pgettext = self.pgettext
+        CONTEXT_SEPARATOR = '\x04'
 
         class AttributiveTranslationString(UserString):
             def __init__(self, data):
                 super().__init__(gettext(data))
                 self.raw_data = data
 
             def __getattr__(self, item):
-                return pgettext(item, self.raw_data)
+                msg_with_ctxt = f'{item}{CONTEXT_SEPARATOR}{self.raw_data}'
+                if CONTEXT_SEPARATOR not in (result := gettext(msg_with_ctxt)):
+                    return result
+                return self.data
 
         return AttributiveTranslationString(message)
-
-
-class NoContextFallbackTranslations(GNUTranslations):
-    def pgettext(self, context, message):
-        return self.gettext(message)