config: Add List ConfigValue and tests.

mopidy/utils/config.py

@@ -1,5 +1,7 @@
 from __future__ import unicode_literals
 
+import re
+
 
 def validate_choice(value, choices):
     """Choice validation, normally called in config value's validate()."""
@@ -109,3 +111,14 @@ class Boolean(ConfigValue):
             return 'true'
         else:
             return 'false'
+
+
+class List(ConfigValue):
+    def deserialize(self, value):
+        if '\n' in value:
+            return re.split(r'\s*\n\s*', value.strip())
+        else:
+            return re.split(r',\s*', value.strip())
+
+    def serialize(self, value):
+        return '\n  '.join(value)

tests/utils/config_test.py

@@ -175,3 +175,20 @@ class BooleanTest(unittest.TestCase):
     def test_format_masks_secrets(self):
         value = config.Boolean(secret=True)
         self.assertEqual('********', value.format('true'))
+
+
+class ListTest(unittest.TestCase):
+    def test_deserialize_splits_commas(self):
+        value = config.List()
+        self.assertEqual(['foo', 'bar', 'baz'],
+                         value.deserialize('foo, bar,baz'))
+
+    def test_deserialize_splits_newlines(self):
+        value = config.List()
+        self.assertEqual(['foo,bar', 'bar', 'baz'],
+                         value.deserialize('foo,bar\nbar\nbaz'))
+
+    def test_serialize_joins_by_newlines(self):
+        value = config.List()
+        self.assertRegexpMatches(value.serialize(['foo', 'bar', 'baz']),
+                                                 r'foo\n\s*bar\n\s*baz')