Merge branch 'factory-fix' of https://github.com/mattupstate/flask-restful into mattupstate-factory-fix

Conflicts:
	flask_restful/__init__.py
	tests/test_api.py

Author: Doug Black

flask_restful/__init__.py

@@ -308,7 +308,6 @@ def handle_error(self, e):
 
         if code == 401:
             resp = self.unauthorized(resp)
-
         return resp
 
     def mediatypes_method(self):
@@ -345,7 +344,6 @@ def add_resource(self, resource, *urls, **kwargs):
         else:
             self.resources.append((resource, urls, kwargs))
 
-
     def _register_view(self, app, resource, *urls, **kwargs):
         endpoint = kwargs.pop('endpoint', None) or resource.__name__.lower()
         self.endpoints.add(endpoint)
@@ -364,7 +362,6 @@ def _register_view(self, app, resource, *urls, **kwargs):
         for decorator in self.decorators:
             resource_func = decorator(resource_func)
 
-
         for url in urls:
             # If this Api has a blueprint
             if self.blueprint:

flask_restful/types.py

@@ -201,6 +201,8 @@ def int_range(low, high, value, argument='argument'):
 
 def boolean(value):
     """Parse the string "true" or "false" as a boolean (case insensitive)"""
+    if not value:
+        raise ValueError("boolean type must be non-null")
     value = value.lower()
     if value == 'true':
         return True