Fix null executor warnings

docs/CHANGELOG.rst

@@ -18,6 +18,7 @@ Added
 Changed
 -------
 - Make processing container startup script ``Python`` 3.12 compatible
+- Fix stop null executor processing in the preparation phase
 
 Fixed
 -----

resolwe/flow/executors/null/prepare.py

@@ -8,7 +8,7 @@
 method.
 """
 
-from resolwe.flow.models import Worker
+from resolwe.flow.models import Data, Worker
 
 from ..prepare import BaseFlowExecutorPreparer  # noqa: F401
 
@@ -19,7 +19,9 @@ class FlowExecutorPreparer(BaseFlowExecutorPreparer):
     def prepare_for_execution(self, data):
         """Prepare the data object for the execution.
 
-        Mark worker object as done.
+        Mark data and its worker object as completed.
         """
+        data.status = Data.STATUS_DONE
         data.worker.status = Worker.STATUS_COMPLETED
-        data.worker.save()
+        data.worker.save(update_fields=["status"])
+        data.save(update_fields=["status"])

resolwe/flow/tests/test_executors.py

@@ -791,12 +791,11 @@ def test_docker_uid_gid(self):
         data = self.run_process("test-docker-uid-gid")
         self.assertEqual(data.output["result"], "OK")
 
-    @unittest.skip("Null executor test currently not working.")
     @with_null_executor
     @tag_process("test-save-number")
     def test_null_executor(self):
         data = self.run_process(
-            "test-save-number", {"number": 19}, assert_status=Data.STATUS_WAITING
+            "test-save-number", {"number": 19}, assert_status=Data.STATUS_DONE
         )
         self.assertEqual(data.input["number"], 19)
         self.assertEqual(data.output, {})