SNS create_topic should only accept valid characters (#1329)

* SNS create_topic should only accept valid characters

Closes #1328

* Fix flake8 errors

* Updated regex to match full TopicName constraints

Fixed test_server as it contained invalid TopicNames’ per constraints

* fix error message for invalid topic name

moto/sns/exceptions.py

@@ -32,3 +32,11 @@ class SNSInvalidParameter(RESTError):
     def __init__(self, message):
         super(SNSInvalidParameter, self).__init__(
             "InvalidParameter", message)
+
+
+class InvalidParameterValue(RESTError):
+    code = 400
+
+    def __init__(self, message):
+        super(InvalidParameterValue, self).__init__(
+            "InvalidParameterValue", message)

moto/sns/models.py

@@ -7,6 +7,7 @@ import json
 import boto.sns
 import requests
 import six
+import re
 
 from moto.compat import OrderedDict
 from moto.core import BaseBackend, BaseModel
@@ -15,7 +16,8 @@ from moto.sqs import sqs_backends
 from moto.awslambda import lambda_backends
 
 from .exceptions import (
-    SNSNotFoundError, DuplicateSnsEndpointError, SnsEndpointDisabled, SNSInvalidParameter
+    SNSNotFoundError, DuplicateSnsEndpointError, SnsEndpointDisabled, SNSInvalidParameter,
+    InvalidParameterValue
 )
 from .utils import make_arn_for_topic, make_arn_for_subscription
 
@@ -193,6 +195,9 @@ class SNSBackend(BaseBackend):
         self.sms_attributes.update(attrs)
 
     def create_topic(self, name):
+        fails_constraints = not re.match(r'^[a-zA-Z0-9](?:[A-Za-z0-9_-]{0,253}[a-zA-Z0-9])?$', name)
+        if fails_constraints:
+            raise InvalidParameterValue("Topic names must be made up of only uppercase and lowercase ASCII letters, numbers, underscores, and hyphens, and must be between 1 and 256 characters long.")
         candidate_topic = Topic(name, self)
         if candidate_topic.arn in self.topics:
             return self.topics[candidate_topic.arn]