From 4f11ac77aede97af8edb00098561c838af2557ad Mon Sep 17 00:00:00 2001
From: Thomas Adamcik <thomas@adamcik.no>
Date: Thu, 27 Dec 2012 03:20:05 +0100
Subject: [PATCH] settings: Update settings validator to support empty
 iterables.

---
 mopidy/utils/settings.py     | 22 ++++++++++++++--------
 tests/utils/settings_test.py |  4 ++--
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/mopidy/utils/settings.py b/mopidy/utils/settings.py
index 6eb462ce..8ae61e5b 100644
--- a/mopidy/utils/settings.py
+++ b/mopidy/utils/settings.py
@@ -142,7 +142,13 @@ def validate_settings(defaults, settings):
         'SPOTIFY_LIB_CACHE': 'SPOTIFY_CACHE_PATH',
     }
 
-    list_of_one_or_more = [
+    must_be_iterable = [
+        'BACKENDS',
+        'FRONTENDS',
+        'STREAM_PROTOCOLS',
+    ]
+
+    must_have_value_set = [
         'BACKENDS',
         'FRONTENDS',
     ]
@@ -171,13 +177,13 @@ def validate_settings(defaults, settings):
                 'Deprecated setting, please set the value via the GStreamer '
                 'bin in OUTPUT.')
 
-        elif setting in list_of_one_or_more:
-            if not hasattr(value, '__iter__'):
-                errors[setting] = (
-                    'Must be a tuple. '
-                    "Remember the comma after single values: (u'value',)")
-            if not value:
-                errors[setting] = 'Must contain at least one value.'
+        elif setting in must_be_iterable and not hasattr(value, '__iter__'):
+            errors[setting] = (
+                'Must be a tuple. '
+                "Remember the comma after single values: (u'value',)")
+
+        elif setting in must_have_value_set and not value:
+            errors[setting] = 'Must be set.'
 
         elif setting not in defaults and not setting.startswith('CUSTOM_'):
             errors[setting] = 'Unknown setting.'
diff --git a/tests/utils/settings_test.py b/tests/utils/settings_test.py
index 1dcac1bb..51f0d89c 100644
--- a/tests/utils/settings_test.py
+++ b/tests/utils/settings_test.py
@@ -79,13 +79,13 @@ class ValidateSettingsTest(unittest.TestCase):
         result = setting_utils.validate_settings(
             self.defaults, {'FRONTENDS': []})
         self.assertEqual(
-            result['FRONTENDS'], 'Must contain at least one value.')
+            result['FRONTENDS'], 'Must be set.')
 
     def test_empty_backends_list_returns_error(self):
         result = setting_utils.validate_settings(
             self.defaults, {'BACKENDS': []})
         self.assertEqual(
-            result['BACKENDS'], 'Must contain at least one value.')
+            result['BACKENDS'], 'Must be set.')
 
     def test_noniterable_multivalue_setting_returns_error(self):
         result = setting_utils.validate_settings(