The following example `serverless.yml` fails to deploy on localstack:

```yaml
service: "localtest"

provider:
  name: "aws"
  runtime: "nodejs10.x"

functions:
  hello:
    handler: "handler.hello"
    
resources:
  Resources:
    ApiGatewayRestApi:
      Type: "AWS::ApiGateway::RestApi"
      Properties:
        Name: "${self:provider.stage}-${self:service}"
    GatewayResponseDefault400:
      Type: "AWS::ApiGateway::GatewayResponse"
      Properties:
        RestApiId:
          Ref: "ApiGatewayRestApi"
        ResponseType: "DEFAULT_4XX"
        ResponseTemplates:
          application/json: '{"errors":[{"message":"Custom text."}]}'
    GatewayResponseUnauthorized:
      Type: "AWS::ApiGateway::GatewayResponse"
      Properties:
        RestApiId:
          Ref: "ApiGatewayRestApi"
        ResponseType: "UNAUTHORIZED"
        ResponseTemplates:
          application/json: '{"errors":[{"message":"Custom text!", "extra":"Some extra info"}]}'
    GatewayResponseDefault500:
      Type: "AWS::ApiGateway::GatewayResponse"
      Properties:
        RestApiId:
          Ref: "ApiGatewayRestApi"
        ResponseType: "DEFAULT_5XX"
        ResponseTemplates:
          application/json: '{"errors":[{"message":$context.error.messageString}]}'
    GatewayResponseIntegrationTimeout:
      Type: "AWS::ApiGateway::GatewayResponse"
      Properties:
        RestApiId:
          Ref: "ApiGatewayRestApi"
        ResponseType: "INTEGRATION_TIMEOUT"
        ResponseTemplates:
          application/json: '{"errors":[{"message":$context.error.messageString}]}'

plugins:
- "serverless-localstack"

custom:
  localstack:
    stages:
      - "local"
```

The error on the localstack end is `Exception: CloudFormation deployment for resource type ApiGateway::GatewayResponse not yet implemented`.
cloudformation = aws_stack.connect_to_service('cloudformation')
        invalid_json = '{"this is invalid JSON"="bobbins"}'
        try:
            cloudformation.validate_template(TemplateBody=invalid_json)
            self.fail('Should raise ValidationError')
        except (ClientError, ResponseParserError) as err:
            if isinstance(err, ClientError):
                self.assertEqual(err.response['ResponseMetadata']['HTTPStatusCode'], 400)
                self.assertEqual(err.response['Error']['Message'], 'Template Validation Error')
    def test_list_stack_resources_returns_queue_urls(self):
        cloudformation = aws_stack.connect_to_resource('cloudformation')
        template = template_deployer.template_to_json(load_file(TEST_TEMPLATE_2))
        cloudformation.create_stack(StackName=TEST_STACK_NAME_2, TemplateBody=template)
        def check_stack():
            stack = get_stack_details(TEST_STACK_NAME_2)
            self.assertEqual(stack['StackStatus'], 'CREATE_COMPLETE')
        retry(check_stack, retries=3, sleep=2)
        stack_summaries = list_stack_resources(TEST_STACK_NAME_2)
        queue_urls = get_queue_urls()
        topic_arns = get_topic_arns()
        stack_queues = [r for r in stack_summaries if r['ResourceType'] == 'AWS::SQS::Queue']
        for resource in stack_queues:
            self.assertIn(resource['PhysicalResourceId'], queue_urls)
        stack_topics = [r for r in stack_summaries if r['ResourceType'] == 'AWS::SNS::Topic']
        for resource in stack_topics:
            self.assertIn(resource['PhysicalResourceId'], topic_arns)