grid.promise: send EmptyResult if promise is test less or anomaly less

There is now `EmptyResult` object which is an empty promise result. This result is send if the promise test or anomaly was skiped (if disabled).
To prevent raise because `EmptyResult` is unknonwn on old slapos-node with `slapos.core < 1.4.17` we will send an empty TestResult instead.

slapos/grid/promise/__init__.py

@@ -49,6 +49,7 @@ from slapos.grid.promise.generic import (GenericPromise, PromiseQueueResult,
                                          PROMISE_PARAMETER_NAME,
                                          PROMISE_PERIOD_FILE_NAME)
 from slapos.grid.promise.wrapper import WrapPromise
+from slapos.version import version
 
 class PromiseError(Exception):
   pass
@@ -492,7 +493,7 @@ class PromiseLauncher(object):
         message="Error: No output returned by the promise",
         execution_time=execution_time
       )
-    elif queue_item.item is None:
+    elif queue_item.item.type() == "Empty Result":
       # no result collected (sense skipped)
       skipped_method = "Anomaly" if self.check_anomaly else "Test"
       self.logger.debug("Skipped, %s is disabled in promise %r." % (
@@ -530,6 +531,7 @@ class PromiseLauncher(object):
       'partition-id': self.partition_id,
       'computer-id': self.computer_id,
       'queue': self.queue_result,
+      'slapgrid-version': version,
     }
 
     if os.path.exists(self.promise_folder) and os.path.isdir(self.promise_folder):

slapos/grid/promise/generic.py

@@ -92,6 +92,15 @@ class AnomalyResult(BaseResult):
   def type():
     return "Anomaly Result"
 
+class EmptyResult(BaseResult):
+
+  def __init__(self):
+    BaseResult.__init__(self, False, None, None)
+
+  @staticmethod
+  def type():
+    return "Empty Result"
+
 class PromiseQueueResult(object):
 
   def __init__(self, path=None, name=None, title=None,
@@ -101,6 +110,9 @@ class PromiseQueueResult(object):
     self.item = item
     self.title = title
     self.execution_time = execution_time
+    if self.item is None:
+      # if no result set, then set EmptyResult
+      self.item = EmptyResult()
 
   def serialize(self):
     return {
@@ -245,7 +257,7 @@ class GenericPromise(with_metaclass(ABCMeta, object)):
     """
     self.__is_anomaly_detected = False
 
-  def isAnomalyLess(self):
+  def isAnomalyDetected(self):
     return self.__is_anomaly_detected
 
   def __bang(self, message):
@@ -487,6 +499,10 @@ class GenericPromise(with_metaclass(ABCMeta, object)):
     elif (not self.__is_tested and not check_anomaly) or \
         (not self.__is_anomaly_detected and check_anomaly):
       # Anomaly or Test is disabled on this promise, send empty result
+      if self.getConfig('slapgrid-version', '') <= '1.4.17':
+        # old version cannot send EmptyResult
+        self.__sendResult(PromiseQueueResult(item=TestResult()))
+      else:
         self.__sendResult(PromiseQueueResult())
     else:
       try: