renamed to_list function to arg_to_list, added docstring and one more test

--HG--
extra : convert_revision : svn%3Ab85faa78-f9eb-468e-a121-7cced6da292c%40939

scrapy/trunk/scrapy/tests/test_utils_misc.py

@@ -1,7 +1,7 @@
 import unittest
 from cStringIO import StringIO
 
-from scrapy.utils.misc import hash_values, items_to_csv, load_object, to_list
+from scrapy.utils.misc import hash_values, items_to_csv, load_object, arg_to_list
 from scrapy.item import ScrapedItem
 
 class UtilsMiscTestCase(unittest.TestCase):
@@ -61,10 +61,11 @@ class UtilsMiscTestCase(unittest.TestCase):
         self.assertRaises(ImportError, load_object, 'nomodule999.mod.function')
         self.assertRaises(NameError, load_object, 'scrapy.utils.misc.load_object999')
 
-    def test_to_list(self):
-        self.assertEqual(to_list(None), [])
-        self.assertEqual(to_list('lala'), ['lala'])
-        self.assertEqual(to_list(('lala', 'poo')), ['lala', 'poo'])
+    def test_arg_to_list(self):
+        self.assertEqual(arg_to_list(None), [])
+        self.assertEqual(arg_to_list('lala'), ['lala'])
+        self.assertEqual(arg_to_list(100), [100])
+        self.assertEqual(arg_to_list(('lala', 'poo')), ['lala', 'poo'])
 
 if __name__ == "__main__":
     unittest.main()

scrapy/trunk/scrapy/utils/misc.py

@@ -14,13 +14,19 @@ from scrapy.utils.python import flatten, unicode_to_str
 from scrapy.utils.markup import remove_entities
 from scrapy.utils.defer import defer_succeed
 
-def to_list(obj):
-    if obj is None:
+def arg_to_list(arg):
+    """Convert an argument to list, so that it can be iterated. The argument
+    can be a None, single value, or an iterable. 
+    
+    This is meant to be used in functions for arguments which can be either
+    None, single valued or multi-valued.
+    """
+    if arg is None:
         return []
-    elif hasattr(obj, '__iter__'):
-        return list(obj)
+    elif hasattr(arg, '__iter__'):
+        return list(arg)
     else:
-        return [obj]
+        return [arg]
 
 def dict_updatedefault(D, E, **F):
     """