Merge pull request #227 from bochecha/noneof

New NoneOf validator

CHANGES.rst

@@ -21,6 +21,8 @@ Features
 - Add a ``missing_msg`` argument to ``SchemaNode``, allowing customization
   of the error message used when the node is required and missing.
 
+- Add `NoneOf` validator wich succeeds if the value is none of the choices.
+
 Bug Fixes
 ---------
 

colander/__init__.py

@@ -443,6 +443,33 @@ class OneOf(object):
                     mapping={'val':value, 'choices':choices})
             raise Invalid(node, err)
 
+
+class NoneOf(object):
+    """ Validator which succeeds if the value passed to it is none of a
+    fixed set of values.
+
+    ``msg_err`` is used to form the ``msg`` of the :exc:`colander.Invalid`
+    error when reporting a validation failure.  If ``msg_err`` is specified,
+    it must be a string.  The string may contain the replacement targets
+    ``${choices}`` and ``${val}``, representing the set of forbidden values
+    and the provided value respectively.
+    """
+    _MSG_ERR = _('"${val}" must not be one of ${choices}')
+
+    def __init__(self, choices, msg_err=_MSG_ERR):
+        self.forbidden = choices
+        self.msg_err = msg_err
+
+    def __call__(self, node, value):
+        if value not in self.forbidden:
+            return
+
+        choices = ', '.join(['%s' % x for x in self.forbidden])
+        err = _(self.msg_err, mapping={'val': value, 'choices': choices})
+
+        raise Invalid(node, err)
+
+
 class ContainsOnly(object):
     """ Validator which succeeds if the value passed to is a sequence and each
     element in the sequence is also in the sequence passed as ``choices``.

colander/tests/test_colander.py

@@ -490,6 +490,22 @@ class TestOneOf(unittest.TestCase):
         e = invalid_exc(validator, None, None)
         self.assertEqual(e.msg.interpolate(), '"None" is not one of 1, 2')
 
+
+class TestNoneOf(unittest.TestCase):
+    def _makeOne(self, values):
+        from colander import NoneOf
+        return NoneOf(values)
+
+    def test_success(self):
+        validator = self._makeOne([1, 2])
+        self.assertEqual(validator(None, 3), None)
+
+    def test_failure(self):
+        validator = self._makeOne([1, 2])
+        e = invalid_exc(validator, None, 2)
+        self.assertEqual(e.msg.interpolate(), '"2" must not be one of 1, 2')
+
+
 class TestContainsOnly(unittest.TestCase):
     def _makeOne(self, values):
         from colander import ContainsOnly

docs/api.rst

@@ -64,6 +64,8 @@ Validators
 
   .. autoclass:: OneOf
 
+  .. autoclass:: NoneOf
+
   .. autoclass:: ContainsOnly
 
   .. autoclass:: Function