[validation] Refactor section type validations

Since Section type is now always set by default
to 'n.s.' the previous section type validations
have been updated as well and the corresponding
messages have been changed.

Author: mpsonntag

odml/validation.py

@@ -133,13 +133,12 @@ def object_required_attributes(obj):
     args = obj.format().arguments
     for arg in args:
         if arg[1] == 1:
+            msg = "Missing required attribute '%s'" % (arg[0])
             if not hasattr(obj, arg[0]):
-                msg = "Missing attribute %s for %s" % (arg[0], obj.format().name.capitalize())
                 yield ValidationError(obj, msg, LABEL_ERROR)
                 continue
             obj_arg = getattr(obj, arg[0])
             if not obj_arg and not isinstance(obj_arg, bool):
-                msg = "%s %s undefined" % (obj.format().name.capitalize(), arg[0])
                 yield ValidationError(obj, msg, LABEL_ERROR)
 
 
@@ -150,12 +149,12 @@ def object_required_attributes(obj):
 
 def section_type_must_be_defined(sec):
     """
-    Tests that no Section has an undefined type.
+    Tests that no Section has an unspecified type and adds a warning otherwise.
 
     :param sec: odml.Section.
     """
-    if sec.type is None or sec.type == '' or sec.type == 'undefined':
-        yield ValidationError(sec, 'Section type undefined', LABEL_WARNING)
+    if sec.type and sec.type == "n.s.":
+        yield ValidationError(sec, "Section type not specified", LABEL_WARNING)
 
 
 Validation.register_handler('section', section_type_must_be_defined)