Make non-null fields required

src/picklefield/fields.py

@@ -81,6 +81,7 @@ class PickledObjectField(models.Field):
     can still do lookups using None). This way, it is still possible to
     use the ``isnull`` lookup type correctly.
     """
+    empty_strings_allowed = False
 
     def __init__(self, *args, **kwargs):
         self.compress = kwargs.pop('compress', False)

src/picklefield/tests.py

@@ -64,7 +64,7 @@ def testDataIntegrity(self):
 
         # Make sure the default value for default_pickled_field gets stored
         # correctly and that it isn't converted to a string.
-        model_test = TestingModel()
+        model_test = TestingModel(pickle_field=1, compressed_pickle_field=1)
         model_test.save()
         model_test = TestingModel.objects.get(id__exact=model_test.id)
         self.assertEqual((D1, S1, T1, L1), model_test.default_pickle_field)
@@ -200,3 +200,7 @@ def testNoCopy(self):
                 compressed_pickle_field='Copy Me',
                 non_copying_field='Dont copy me'
             )
+
+    def testAllNonNullFieldsNeedToBeSetForSave(self):
+        with self.assertRaises(django.db.IntegrityError):
+            MinimalTestingModel.objects.create()