Complete coverage for IS_IN_SET

Removed unreachable code in IS_IN_SET
        if failures and self.theset:
            if self.multiple and (value is None or value == '')
It's impossible to have *failures* and have value be None or '' at the same time

gluon/tests/test_validators.py

@@ -184,6 +184,10 @@ class TestValidators(unittest.TestCase):
         self.assertEqual(rtn, ('id1', None))
         rtn = IS_IN_SET(['id1', 'id2'], error_message='oops', multiple=True)(None)
         self.assertEqual(rtn, ([], None))
+        rtn = IS_IN_SET(['id1', 'id2'], error_message='oops', multiple=True)('')
+        self.assertEqual(rtn, ([], None))
+        rtn = IS_IN_SET(['id1', 'id2'], error_message='oops', multiple=True)('id1')
+        self.assertEqual(rtn, (['id1'], None))
         rtn = IS_IN_SET(['id1', 'id2'], error_message='oops', multiple=(1,2))(None)
         self.assertEqual(rtn, ([], 'oops'))
         import itertools

gluon/validators.py

@@ -471,8 +471,6 @@ class IS_IN_SET(Validator):
         thestrset = [str(x) for x in self.theset]
         failures = [x for x in values if not str(x) in thestrset]
         if failures and self.theset:
-            if self.multiple and (value is None or value == ''):
-                return ([], None)
             return (value, translate(self.error_message))
         if self.multiple:
             if isinstance(self.multiple, (tuple, list)) and \