chore: adding comments to test_sns_helper.py

test/aws/osml/model_runner/status/test_sns_helper.py

@@ -10,15 +10,21 @@
 from botocore.exceptions import ClientError
 from moto import mock_aws
 
+# Mock to simulate a ClientError when trying to publish to SNS
 TEST_MOCK_PUBLISH_EXCEPTION = Mock(side_effect=ClientError({"Error": {"Code": 500, "Message": "ClientError"}}, "publish"))
 
 
 @mock_aws
 class TestSnsHelper(TestCase):
     def setUp(self):
+        """
+        Set up the mock AWS environment. This includes creating an SNS topic and an SQS queue,
+        subscribing the queue to the SNS topic, and initializing the SNSHelper instance.
+        """
         from aws.osml.model_runner.app_config import BotoConfig
         from aws.osml.model_runner.status.sns_helper import SNSHelper
 
+        # Initialize mock SNS and SQS clients
         self.sns = boto3.client("sns", config=BotoConfig.default)
         sns_response = self.sns.create_topic(Name=os.environ["IMAGE_STATUS_TOPIC"])
         self.mock_topic_arn = sns_response.get("TopicArn")
@@ -29,25 +35,38 @@ def setUp(self):
         queue_attributes = self.sqs.get_queue_attributes(QueueUrl=self.mock_queue_url, AttributeNames=["QueueArn"])
         queue_arn = queue_attributes.get("Attributes").get("QueueArn")
 
+        # Subscribe the mock SQS queue to the SNS topic
         self.sns.subscribe(TopicArn=self.mock_topic_arn, Protocol="sqs", Endpoint=queue_arn)
 
+        # Initialize SNSHelper with the mock topic ARN
         self.image_status_sns = SNSHelper(self.mock_topic_arn)
 
     def tearDown(self):
+        """
+        Clean up by setting all instance variables to None.
+        """
         self.sns = None
         self.mock_topic_arn = None
         self.sqs = None
         self.mock_queue_url = None
         self.image_status_sns = None
 
     def test_publish_message_success(self):
+        """
+        Test that a valid message with string and binary attributes is successfully published to SNS
+        and received by the subscribed SQS queue. Verify that message attributes are correctly transformed.
+        """
         mock_message = "test message 1"
         mock_attributes = {"key1": "string data", "bin1": b"binary data"}
         expected_attributes = {
             "key1": {"Type": "String", "Value": "string data"},
-            "bin1": {"Type": "Binary", "Value": "YmluYXJ5IGRhdGE="},
+            "bin1": {"Type": "Binary", "Value": "YmluYXJ5IGRhdGE="},  # Base64 encoded binary data
         }
+
+        # Publish the message
         self.image_status_sns.publish_message(mock_message, mock_attributes)
+
+        # Retrieve and verify the message from the mock SQS queue
         messages = self.sqs.receive_message(QueueUrl=self.mock_queue_url, MessageAttributeNames=["key1", "bin1"]).get(
             "Messages"
         )
@@ -57,13 +76,21 @@ def test_publish_message_success(self):
         assert message_body.get("MessageAttributes") == expected_attributes
 
     def test_publish_message_success_drop_invalid_types(self):
+        """
+        Test that a message with invalid attribute types (e.g., integer) drops the invalid attributes
+        and only publishes valid string and binary attributes.
+        """
         mock_message = "test invalid data gets removed"
         mock_attributes = {"key1": "string data", "bin1": b"binary data", "invalid_int_data": 1}
         expected_attributes = {
             "key1": {"Type": "String", "Value": "string data"},
-            "bin1": {"Type": "Binary", "Value": "YmluYXJ5IGRhdGE="},
+            "bin1": {"Type": "Binary", "Value": "YmluYXJ5IGRhdGE="},  # Base64 encoded binary data
         }
+
+        # Publish the message
         self.image_status_sns.publish_message(mock_message, mock_attributes)
+
+        # Retrieve and verify the message from the mock SQS queue
         messages = self.sqs.receive_message(QueueUrl=self.mock_queue_url, MessageAttributeNames=["key1", "bin1"]).get(
             "Messages"
         )
@@ -73,20 +100,33 @@ def test_publish_message_success_drop_invalid_types(self):
         assert message_body.get("MessageAttributes") == expected_attributes
 
     def test_publish_message_failure(self):
+        """
+        Test that when the SNS publish operation fails, an SNSPublishException is raised.
+        """
         from aws.osml.model_runner.status.exceptions import SNSPublishException
 
+        # Mock the publish method to simulate a failure
         self.image_status_sns.sns_client.publish = TEST_MOCK_PUBLISH_EXCEPTION
         mock_message = "test message 1"
         mock_attributes = {"key1": "string data", "bin1": b"binary data"}
+
+        # Expecting SNSPublishException due to the mock exception
         with self.assertRaises(SNSPublishException):
             self.image_status_sns.publish_message(mock_message, mock_attributes)
 
     def test_publish_message_no_topic(self):
+        """
+        Test that if no SNS topic is configured, the publish_message method should gracefully return None
+        and not attempt to send a message.
+        """
         from aws.osml.model_runner.status.sns_helper import SNSHelper
 
+        # Initialize SNSHelper with no topic
         image_status_sns = SNSHelper(None)
         mock_message = "test message 1"
         mock_attributes = {"key1": "string data", "bin1": b"binary data"}
+
+        # Verify that publishing returns None when no topic is configured
         response = image_status_sns.publish_message(mock_message, mock_attributes)
         assert response is None