/**
  * Returns true if result status is UNKNOWN or any of the subresult status is unknown (recursive).
  *
  * <p>May come handy in tests to check if all the operations fill out the status as they should.
  */
 public boolean hasUnknownStatus() {
   if (status == OperationResultStatus.UNKNOWN) {
     return true;
   }
   for (OperationResult subresult : getSubresults()) {
     if (subresult.hasUnknownStatus()) {
       return true;
     }
   }
   return false;
 }