Report error if modes is invalid

Author: alahiff

simvue/run.py

@@ -190,6 +190,9 @@ def init(self, name=None, metadata={}, tags=[], description=None, folder='/', ru
         """
         Initialise a run
         """
+        if self._mode not in ('online', 'offline', 'disabled'):
+            self._error('invalid mode specified, must be online, offline or disabled')
+
         if self._mode == 'disabled':
             return True