Route53 should raise an exception when record already exists

[1oglop1]

Hi, I'm trying to mock route53 and test my function, however, I noticed that moto does not raise an exception that real route53 does. This does apply for CREATE and DELETE actions maybe even for UPSERT

moto version = 3.1.4

How to reproduce

Call route53_client.change_resource_record_sets two times with the same parameters.

Expected behaviour

1st call -> returns a response

{
    'ChangeInfo': {
        'Id': '...',
        'Status': 'PENDING',
        'SubmittedAt': ...,
        'Comment': '...'
    }
}

2nd call raises an error

Actual behaviour

1st call returns {'Id': '/change/C2682N5HXP0BZ4', 'Status': 'INSYNC', 'SubmittedAt': datetime.datetime(2010, 9, 10, 1, 36, 41, 958000, tzinfo=tzutc())}

2nd call returns {'Id': '/change/C2682N5HXP0BZ4', 'Status': 'INSYNC', 'SubmittedAt': datetime.datetime(2010, 9, 10, 1, 36, 41, 958000, tzinfo=tzutc())}

I think that problem is likely this response https://github.com/spulec/moto/blob/67ab7f857ac87671578ebb1127ec971d030ec43a/moto/route53/responses.py#L156-L160

Example code:

import boto3
import botocore.exceptions
import pytest
from moto import mock_route53

ZONE = 'cname.local'
FQDN = f"test.{ZONE}"
FQDN_TARGET = "develop.domain.com"


@pytest.fixture
def route53_client():
    with mock_route53():
        yield boto3.client("route53")


@pytest.fixture
def route53_zone(route53_client):
    resp = route53_client.create_hosted_zone(
        Name=ZONE,
        CallerReference='ref',
        DelegationSetId='string'
    )
    yield resp['HostedZone']['Id']

def create_cname(route53_client):
    return route53_client.change_resource_record_sets(
        HostedZoneId=route53_zone,
        ChangeBatch={
            "Changes": [
                {
                    "Action": "CREATE",
                    "ResourceRecordSet": {
                        "Name": FQDN,
                        "Type": "CNAME",
                        "TTL": 600,
                        "ResourceRecords": [
                            {"Value": FQDN_TARGET},
                        ],
                    },
                },
            ]
        },
    )

def test_r53_create_fail(route53_client, route53_zone, route53_record):
    r = create_cname(route53_client)
    # this should raise route53_client.exceptions.InvalidChangeBatch with message already exists
    # botocore.errorfactory.InvalidChangeBatch: An error occurred (InvalidChangeBatch) when calling the ChangeResourceRecordSets operation: [Tried to create resource record set [name='test.cname.local.', type='CNAME'] but it already exists]
    with pytest.raises(botocore.exceptions.ClientError):
        r2 = route53_client.change_resource_record_sets(
            HostedZoneId=route53_zone,
            ChangeBatch={
                # 'Comment': 'string',
                "Changes": [
                    {
                        "Action": "CREATE",
                        "ResourceRecordSet": {
                            "Name": FQDN,
                            "Type": "CNAME",
                            "TTL": 600,
                            "ResourceRecords": [
                                {"Value": FQDN_TARGET},
                            ],
                        },
                    },
                ]
            },
        )

[bblommers]

Thanks for raising this @1oglop1 - will mark it as an enhancement to implement this validation.