Fix : SNS get attributes on FIFO topic (#4444)

moto/sns/models.py

@@ -53,6 +53,8 @@ class Topic(CloudFormationModel):
             sns_backend.region_name, self.account_id, name
         )
         self._tags = {}
+        self.fifo_topic = "false"
+        self.content_based_deduplication = "false"
 
     def publish(self, message, subject=None, message_attributes=None):
         message_id = str(uuid.uuid4())

moto/sns/responses.py

@@ -170,6 +170,11 @@ class SNSResponse(BaseResponse):
             }
             if topic.kms_master_key_id:
                 attributes["KmsMasterKeyId"] = topic.kms_master_key_id
+            if topic.fifo_topic == "true":
+                attributes["FifoTopic"] = topic.fifo_topic
+                attributes[
+                    "ContentBasedDeduplication"
+                ] = topic.content_based_deduplication
             response = {
                 "GetTopicAttributesResponse": {
                     "GetTopicAttributesResult": {"Attributes": attributes},
@@ -836,6 +841,16 @@ GET_TOPIC_ATTRIBUTES_TEMPLATE = """<GetTopicAttributesResponse xmlns="http://sns
         <value>{{ topic.kms_master_key_id }}</value>
       </entry>
       {% endif %}
+      {% if topic.fifo_topic == 'true' %}
+      <entry>
+        <key>FifoTopic</key>
+        <value>{{ topic.fifo_topic }}</value>
+      </entry>
+      <entry>
+        <key>ContentBasedDeduplication</key>
+        <value>{{ topic.content_based_deduplication }}</value>
+      </entry>
+      {% endif %}
     </Attributes>
   </GetTopicAttributesResult>
   <ResponseMetadata>

tests/test_sns/test_topics_boto3.py

@@ -570,3 +570,51 @@ def test_topic_kms_master_key_id_attribute():
     resp = client.get_topic_attributes(TopicArn=topic_arn)
     resp["Attributes"].should.have.key("KmsMasterKeyId")
     resp["Attributes"]["KmsMasterKeyId"].should.equal("key-id")
+
+
+@mock_sns
+def test_topic_fifo_get_attributes():
+    client = boto3.client("sns", region_name="us-east-1")
+    resp = client.create_topic(
+        Name="test-topic-fifo-get-attr.fifo", Attributes={"FifoTopic": "true"}
+    )
+    topic_arn = resp["TopicArn"]
+    attributes = client.get_topic_attributes(TopicArn=topic_arn)["Attributes"]
+
+    attributes.should.have.key("FifoTopic")
+    attributes.should.have.key("ContentBasedDeduplication")
+
+    attributes["FifoTopic"].should.equal("true")
+    attributes["ContentBasedDeduplication"].should.equal("false")
+
+    client.set_topic_attributes(
+        TopicArn=topic_arn,
+        AttributeName="ContentBasedDeduplication",
+        AttributeValue="true",
+    )
+    attributes = client.get_topic_attributes(TopicArn=topic_arn)["Attributes"]
+    attributes["ContentBasedDeduplication"].should.equal("true")
+
+
+@mock_sns
+def test_topic_get_attributes():
+    client = boto3.client("sns", region_name="us-east-1")
+    resp = client.create_topic(Name="test-topic-get-attr")
+    topic_arn = resp["TopicArn"]
+    attributes = client.get_topic_attributes(TopicArn=topic_arn)["Attributes"]
+
+    attributes.should_not.have.key("FifoTopic")
+    attributes.should_not.have.key("ContentBasedDeduplication")
+
+
+@mock_sns
+def test_topic_get_attributes_with_fifo_false():
+    client = boto3.client("sns", region_name="us-east-1")
+    resp = client.create_topic(
+        Name="test-topic-get-attr-with-fifo-false", Attributes={"FifoTopic": "false"}
+    )
+    topic_arn = resp["TopicArn"]
+    attributes = client.get_topic_attributes(TopicArn=topic_arn)["Attributes"]
+
+    attributes.should_not.have.key("FifoTopic")
+    attributes.should_not.have.key("ContentBasedDeduplication")