TextField: fixed type error bug with empty lists

scrapy/contrib_exp/newitem/fields.py

@@ -120,7 +120,7 @@ class TextField(BaseField):
 
     def to_single(self, value):
         """Converts the input iterable into a single value"""
-        return ' '.join((self.to_python(x) for x in value))
+        return u' '.join((self.to_python(x) for x in value))
 
 
 class TimeField(BaseField):

scrapy/tests/test_newitem.py

@@ -309,6 +309,11 @@ class NewItemFieldsTest(unittest.TestCase):
         self.assertRaises(TypeError, setattr, i, 'field', [u'hello', 3, u'world']) 
         self.assertRaises(TypeError, setattr, i, 'field', [u'hello', 'world']) 
 
+        i = TestItem()
+        i.field = []
+        assert isinstance(i.field, unicode)
+        self.assertEqual(i.field, '')
+
     def test_time_field(self):
         class TestItem(Item):
             field = fields.TimeField()