Fixed error serialization (getredash#6937)

* serialize errors

* lint fix

* cover successful case

redash/serializers/__init__.py

@@ -282,10 +282,17 @@ def serialize_job(job):
     job_result = job.latest_result()
     if job_result:
         if job_result.type == Result.Type.SUCCESSFUL:
-            result_id = job_result.return_value
+            result = job_result.return_value
+            if isinstance(result, Exception):
+                error = str(result)
+                status = JobStatus.FAILED
+            elif isinstance(result, dict) and "error" in result:
+                error = result["error"]
+                status = JobStatus.FAILED
+            else:
+                result_id = result
         else:
             error = job_result.exc_string
-
     return {
         "job": {
             "id": job.id,

tests/serializers/test_job.py

@@ -0,0 +1,81 @@
+from unittest.mock import MagicMock
+
+from rq.job import JobStatus
+from rq.results import Result
+
+from redash.serializers import (
+    serialize_job,
+)
+from redash.tasks.queries.execution import QueryExecutionError
+from tests import BaseTestCase
+
+
+class JobSerializationTest(BaseTestCase):
+    def test_serializes_job_with_exception_in_result(self):
+        job = MagicMock()
+        job.id = 0
+        job.is_started = False
+        job.get_status = MagicMock(return_value=JobStatus.FINISHED)
+        result = MagicMock()
+        result.type = Result.Type.SUCCESSFUL
+        result.return_value = QueryExecutionError("test")
+        job.latest_result = MagicMock(return_value=result)
+        result = serialize_job(job)
+        self.assertDictEqual(
+            result,
+            {
+                "job": {
+                    "id": 0,
+                    "updated_at": 0,
+                    "status": JobStatus.FAILED,
+                    "error": str(QueryExecutionError("test")),
+                    "result_id": None,
+                }
+            },
+        )
+
+    def test_serializes_job_with_dict_that_contains_error_in_result(self):
+        job = MagicMock()
+        job.id = 0
+        job.is_started = False
+        job.get_status = MagicMock(return_value=JobStatus.FINISHED)
+        result = MagicMock()
+        result.type = Result.Type.SUCCESSFUL
+        result.return_value = {"error": "test error"}
+        job.latest_result = MagicMock(return_value=result)
+        result = serialize_job(job)
+        self.assertDictEqual(
+            result,
+            {
+                "job": {
+                    "id": 0,
+                    "updated_at": 0,
+                    "status": JobStatus.FAILED,
+                    "error": "test error",
+                    "result_id": None,
+                }
+            },
+        )
+
+    def test_serializes_job_with_dict_that_finished_successfully(self):
+        job = MagicMock()
+        job.id = 0
+        job.is_started = False
+        job.get_status = MagicMock(return_value=JobStatus.FINISHED)
+        result = MagicMock()
+        result.type = Result.Type.SUCCESSFUL
+        result.return_value = 1
+        job.latest_result = MagicMock(return_value=result)
+        result = serialize_job(job)
+        self.assertDictEqual(
+            result,
+            {
+                "job": {
+                    "id": 0,
+                    "updated_at": 0,
+                    "status": JobStatus.FINISHED,
+                    "error": None,
+                    "result_id": 1,
+                }
+            },
+        )