Merge pull request #24 from toscawidgets/master

Merge @moschlar's hotfix back into develop.

tw2/forms/widgets.py

@@ -60,6 +60,13 @@ class CheckBox(InputField):
     type = "checkbox"
     validator = twc.BoolValidator
 
+    def _validate(self, value, state=None):
+        # Since twc.BoolValidator returns None if no value is present
+        # (which is the common case if a HTML checkbox is not checked)
+        # we explicitly convert to bool again here
+        self.value = super(CheckBox, self)._validate(value, state)
+        return bool(self.value)
+
     def prepare(self):
         super(CheckBox, self).prepare()
         checked = self.validator.to_python(self.value)