compat: support unicode in environment variables

On Python2 we have to encode provide utf-8 bytestrings if we want
unicode values in enviornment variables.  Python3 accepts them as-is.

Related-to: #282
Reported-by: Ｖ字龍(Vdragon) <pika1021@gmail.com>
Signed-off-by: David Aguilar <davvid@gmail.com>

cola/compat.py

@@ -23,12 +23,15 @@
 except ImportError:
     import urllib
 
+
 def setenv(key, value):
     """Compatibility wrapper for setting environment variables
 
     Why?  win32 requires putenv().  UNIX only requires os.environ.
 
     """
+    if not PY3 and type(value) is ustr:
+        value = value.encode('utf-8', 'replace')
     os.environ[key] = value
     os.putenv(key, value)
 

test/compat_test.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+# -*- encoding: utf-8 -*-
+
+from __future__ import unicode_literals
+
+import os
+import unittest
+
+from cola import compat
+
+
+class CompatTestCase(unittest.TestCase):
+    """Tests the compat module"""
+
+    def test_setenv(self):
+        """Test the core.decode function
+        """
+        key = 'COLA_UNICODE_TEST'
+        value = '字龍'
+        compat.setenv(key, value)
+        self.assertTrue(key in os.environ)
+        self.assertTrue(os.getenv(key))
+
+        compat.unsetenv(key)
+        self.assertFalse(key in os.environ)
+        self.assertFalse(os.getenv(key))
+
+
+if __name__ == '__main__':
+    unittest.main()