Added tests

IPython/utils/tests/test_traitlets.py

@@ -16,7 +16,7 b' import nose.tools as nt'
 from nose import SkipTest
 
 from IPython.utils.traitlets import (
-    HasTraits, MetaHasTraits, TraitType, Any, CBytes, Dict,
+    HasTraits, MetaHasTraits, TraitType, AllowNone, Any, CBytes, Dict,
     Int, Long, Integer, Float, Complex, Bytes, Unicode, TraitError,
     Undefined, Type, This, Instance, TCPAddress, List, Tuple,
     ObjectName, DottedObjectName, CRegExp, link
@@ -73,7 +73,7 b' class TestTraitType(TestCase):'
         self.assertEqual(a.tt, -1)
 
     def test_default_validate(self):
-        class MyIntTT(TraitType):
+        class MyIntTT(AllowNone):
             def validate(self, obj, value):
                 if isinstance(value, int):
                     return value
@@ -673,6 +673,23 b' class TraitTestBase(TestCase):'
         if hasattr(self, '_default_value'):
             self.assertEqual(self._default_value, self.obj.value)
 
+    def test_allow_none(self):
+        if (hasattr(self, '_bad_values') and hasattr(self, '_good_values') and
+        None in self._bad_values):
+            trait=self.obj.traits()['value']
+            if isinstance(trait, AllowNone) and not trait._allow_none:
+                trait._allow_none = True
+                self._bad_values.remove(None)
+                #skip coerce. Allow None casts None to None.
+                self.assign(None)
+                self.assertEqual(self.obj.value,None)
+                self.test_good_values()
+                self.test_bad_values()
+                #tear down
+                trait._allow_none = False
+                self._bad_values.append(None)
+
+
     def tearDown(self):
         # restore default value after tests, if set
         if hasattr(self, '_default_value'):
@@ -830,7 +847,7 b' class TestObjectName(TraitTestBase):'
     _default_value = "abc"
     _good_values = ["a", "gh", "g9", "g_", "_G", u"a345_"]
     _bad_values = [1, "", u"€", "9g", "!", "#abc", "aj@", "a.b", "a()", "a[0]",
-                                                            object(), object]
+                                                        None, object(), object]
     if sys.version_info[0] < 3:
         _bad_values.append(u"þ")
     else:
@@ -845,7 +862,7 b' class TestDottedObjectName(TraitTestBase):'
 
     _default_value = "a.b"
     _good_values = ["A", "y.t", "y765.__repr__", "os.path.join", u"os.path.join"]
-    _bad_values = [1, u"abc.€", "_.@", ".", ".abc", "abc.", ".abc."]
+    _bad_values = [1, u"abc.€", "_.@", ".", ".abc", "abc.", ".abc.", None]
     if sys.version_info[0] < 3:
         _bad_values.append(u"t.þ")
     else:
@@ -862,7 +879,7 b' class TestTCPAddress(TraitTestBase):'
 
     _default_value = ('127.0.0.1',0)
     _good_values = [('localhost',0),('192.168.0.1',1000),('www.google.com',80)]
-    _bad_values = [(0,0),('localhost',10.0),('localhost',-1)]
+    _bad_values = [(0,0),('localhost',10.0),('localhost',-1), None]
 
 class ListTrait(HasTraits):