# Type of request: This is a ...
[ ] bug report
[x] feature request

# Detailed description
As a Developer,
I want to be able to simulate BadDigest and InvalidDigest errors,
So that I can test the error handling logic

## Expected behavior
https://docs.aws.amazon.com/AmazonS3/latest/API/ErrorResponses.html
BadDigest: The Content-MD5 you specified did not match what we received.
InvalidDigest: The Content-MD5 you specified is not valid.

## Actual behavior
localstack returns InvalidDigest when MD5 does not match payload.


return get_table_not_found_error()
                raise
            
            
            if ((data.get('ReturnValues') == 'ALL_OLD') or (not data.get('ReturnValues'))) \
                    and not data.get('ReturnConsumedCapacity'):
                data['ReturnConsumedCapacity'] = 'TOTAL'
                return Request(data=json.dumps(data), method=method, headers=headers)
        elif action == '%s.DescribeTable' % ACTION_PREFIX:
            
            table_names = ddb_client.list_tables()['TableNames']
            if to_str(data['TableName']) not in table_names:
                return get_table_not_found_error()
        elif action == '%s.DeleteTable' % ACTION_PREFIX:
            
            table_names = ddb_client.list_tables()['TableNames']
            if to_str(data['TableName']) not in table_names:
                return get_table_not_found_error()
        elif action == '%s.BatchWriteItem' % ACTION_PREFIX:
            existing_items = []
            for table_name in sorted(data['RequestItems'].keys()):
                for request in data['RequestItems'][table_name]:
                    for key in ['PutRequest', 'DeleteRequest']:
                        inner_request = request.get(key)
                        if inner_request:
                            existing_items.append(find_existing_item(inner_request, table_name))
            ProxyListenerDynamoDB.thread_local.existing_items = existing_items
        elif action == '%s.TransactWriteItems' % ACTION_PREFIX:
            existing_items = []
            for item in data['TransactItems']: