config: Fix escapes in string handling

mopidy/config/types.py

@@ -81,7 +81,8 @@ class String(ConfigValue):
     """
     def deserialize(self, value):
         if not isinstance(value, unicode):
-            value = value.decode('utf-8')
+            # TODO: only unescape \n \t and \\?
+            value = value.decode('string-escape').decode('utf-8')
         value = value.strip()
         validators.validate_required(value, not self.optional)
         validators.validate_choice(value, self.choices)
@@ -90,7 +91,11 @@ class String(ConfigValue):
         return value
 
     def serialize(self, value):
-        return value.encode('utf-8').encode('string-escape')
+        if isinstance(value, unicode):
+            for char in ('\\', '\n', '\t'):  # TODO: more escapes?
+                value = value.replace(char, char.encode('unicode-escape'))
+            value = value.encode('utf-8')
+        return value
 
 
 class Integer(ConfigValue):

tests/config/types_test.py

@@ -65,7 +65,10 @@ class StringTest(unittest.TestCase):
         result = value.deserialize('æøå')
         self.assertEqual('æøå', result)
 
-    # TODO: add test_deserialize_decodes_string_escapes
+    def test_deserialize_handles_escapes(self):
+        value = types.String(optional=True)
+        result = value.deserialize(b'a\\t\\nb')
+        self.assertEqual('a\t\nb', result)
 
     def test_deserialize_enforces_choices(self):
         value = types.String(choices=['foo', 'bar', 'baz'])
@@ -88,9 +91,23 @@ class StringTest(unittest.TestCase):
         self.assertRaises(
             ValueError, value.deserialize, incorrectly_encoded_bytes)
 
-    def test_serialize_string_escapes(self):
+    def test_serialize_encodes_utf8(self):
         value = types.String()
-        self.assertEqual(r'\r\n\t', value.serialize('\r\n\t'))
+        result = value.serialize('æøå')
+        self.assertIsInstance(result, bytes)
+        self.assertEqual('æøå'.encode('utf-8'), result)
+
+    def test_serialize_does_not_encode_bytes(self):
+        value = types.String()
+        result = value.serialize('æøå'.encode('utf-8'))
+        self.assertIsInstance(result, bytes)
+        self.assertEqual('æøå'.encode('utf-8'), result)
+
+    def test_serialize_handles_escapes(self):
+        value = types.String()
+        result = value.serialize('a\n\tb')
+        self.assertIsInstance(result, bytes)
+        self.assertEqual(r'a\n\tb'.encode('utf-8'), result)
 
     def test_format_masks_secrets(self):
         value = types.String(secret=True)