[property] Add validation on val_cardinality set

When setting a values cardinality and the current number
of values violate the cardinality a warning is printed to the user.

Author: mpsonntag

odml/property.py

@@ -133,6 +133,8 @@ def __init__(self, name=None, values=None, parent=None, unit=None,
 
         self.parent = parent
 
+        # Cardinality should always be set after values have been added
+        # since it is always tested against values when it is set.
         self._val_cardinality = None
         self.val_cardinality = val_cardinality
 
@@ -572,7 +574,12 @@ def val_cardinality(self, new_value):
         else:
             invalid_input = True
 
-        if invalid_input:
+        if not invalid_input:
+            # Validate and inform user if the current values cardinality is violated
+            valid = validation.Validation(self)
+            for err in valid.errors:
+                print("%s: %s" % (err.rank.capitalize(), err.msg))
+        else:
             msg = "Can only assign single int or int-tuples of the format '(min, max)'"
             raise ValueError(msg)