fix: return empty_dict for job.result() when results not saved (#82)

* fix: return empty_dict when job results not saved

* Handle non-404 errors

* check download_from_s3 instead of download_result

* Add check if results not available in json format in tar

* Return empty_dict if result.json not found

* address comment

src/braket/aws/aws_quantum_job.py

@@ -25,6 +25,7 @@
 from typing import Any, Dict, List
 
 import boto3
+from botocore.exceptions import ClientError
 
 from braket.aws.aws_session import AwsSession
 from braket.jobs import logs
@@ -495,13 +496,27 @@ def result(
 
         with tempfile.TemporaryDirectory() as temp_dir:
             job_name = self.metadata(True)["jobName"]
-            self.download_result(temp_dir, poll_timeout_seconds, poll_interval_seconds)
+
+            try:
+                self.download_result(temp_dir, poll_timeout_seconds, poll_interval_seconds)
+            except ClientError as e:
+                if e.response["Error"]["Code"] == "404":
+                    return {}
+                else:
+                    raise e
+            return AwsQuantumJob._read_and_deserialize_results(temp_dir, job_name)
+
+    @staticmethod
+    def _read_and_deserialize_results(temp_dir, job_name):
+        try:
             with open(f"{temp_dir}/{job_name}/{AwsQuantumJob.RESULTS_FILENAME}", "r") as f:
                 persisted_data = PersistedJobData.parse_raw(f.read())
                 deserialized_data = deserialize_values(
                     persisted_data.dataDictionary, persisted_data.dataFormat
                 )
                 return deserialized_data
+        except FileNotFoundError:
+            return {}
 
     def download_result(
         self,

test/unit_tests/braket/aws/test_aws_quantum_job.py

@@ -397,6 +397,57 @@ def test_download_result_when_extract_path_provided(
             assert expected_saved_data == actual_data
 
 
+def test_empty_dict_returned_when_result_not_saved(
+    quantum_job, generate_get_job_response, aws_session
+):
+    state = "COMPLETED"
+    get_job_response_completed = generate_get_job_response(status=state)
+    aws_session.get_job.return_value = get_job_response_completed
+
+    exception_response = {
+        "Error": {
+            "Code": "404",
+            "Message": "Not Found",
+        }
+    }
+    quantum_job._aws_session.download_from_s3 = Mock(
+        side_effect=ClientError(exception_response, "HeadObject")
+    )
+    assert quantum_job.result() == {}
+
+
+def test_results_raises_error_for_non_404_errors(
+    quantum_job, generate_get_job_response, aws_session
+):
+    state = "COMPLETED"
+    get_job_response_completed = generate_get_job_response(status=state)
+    aws_session.get_job.return_value = get_job_response_completed
+
+    error = "An error occurred \\(402\\) when calling the SomeObject operation: Something"
+
+    exception_response = {
+        "Error": {
+            "Code": "402",
+            "Message": "Something",
+        }
+    }
+    quantum_job._aws_session.download_from_s3 = Mock(
+        side_effect=ClientError(exception_response, "SomeObject")
+    )
+    with pytest.raises(ClientError, match=error):
+        quantum_job.result()
+
+
+@patch("braket.aws.aws_quantum_job.AwsQuantumJob.download_result")
+def test_results_json_file_not_in_tar(
+    result_download, quantum_job, aws_session, generate_get_job_response
+):
+    state = "COMPLETED"
+    get_job_response_completed = generate_get_job_response(status=state)
+    quantum_job._aws_session.get_job.return_value = get_job_response_completed
+    assert quantum_job.result() == {}
+
+
 @pytest.fixture
 def entry_point():
     return "test-source-dir.entry_point:func"