Add locale_decode util function that decodes bytestrings using the current locale's encoding

mopidy/utils/__init__.py

@@ -1,3 +1,4 @@
+import locale
 import logging
 import os
 import sys
@@ -29,3 +30,9 @@ def get_class(name):
     except (ImportError, AttributeError):
         raise ImportError("Couldn't load: %s" % name)
     return class_object
+
+def locale_decode(bytestr):
+    try:
+        return unicode(bytestr)
+    except UnicodeError:
+        return str(bytestr).decode(locale.getpreferredencoding())

tests/utils/decode_test.py

@@ -0,0 +1,38 @@
+import mock
+
+from mopidy.utils import locale_decode
+
+from tests import unittest
+
+
+@mock.patch('mopidy.utils.locale.getpreferredencoding')
+class LocaleDecodeTest(unittest.TestCase):
+    def test_can_decode_utf8_strings_with_french_content(self, mock):
+        mock.return_value = 'UTF-8'
+
+        result = locale_decode(
+            '[Errno 98] Adresse d\xc3\xa9j\xc3\xa0 utilis\xc3\xa9e')
+
+        self.assertEquals(u'[Errno 98] Adresse d\xe9j\xe0 utilis\xe9e', result)
+
+    def test_can_decode_an_ioerror_with_french_content(self, mock):
+        mock.return_value = 'UTF-8'
+
+        error = IOError(98, 'Adresse d\xc3\xa9j\xc3\xa0 utilis\xc3\xa9e')
+        result = locale_decode(error)
+
+        self.assertEquals(u'[Errno 98] Adresse d\xe9j\xe0 utilis\xe9e', result)
+
+    def test_does_not_use_locale_to_decode_unicode_strings(self, mock):
+        mock.return_value = 'UTF-8'
+
+        locale_decode(u'abc')
+
+        self.assertFalse(mock.called)
+
+    def test_does_not_use_locale_to_decode_ascii_bytestrings(self, mock):
+        mock.return_value = 'UTF-8'
+
+        locale_decode('abc')
+
+        self.assertFalse(mock.called)