`put_item` using `batch_writer` does not validate empty strings

[pawelarybak]

Issue similar to #1129 When putting items with empty strings using batch_writer ClientError is not raised.

Using moto==3.1.16

Failing test case:

import pytest
import boto3
import botocore
from moto import mock_dynamodb


@pytest.fixture
def ddb():
    return boto3.resource(
        'dynamodb',
        aws_access_key_id='',
        aws_secret_access_key='',
        region_name='eu-west-1',
    )


@mock_dynamodb
def test_batch_put(ddb):
    ddb.create_table(
        AttributeDefinitions=[{"AttributeName": "value", "AttributeType": "S"}],
        TableName="test_table",
        KeySchema=[{"AttributeName": "value", "KeyType": "HASH"}],
        ProvisionedThroughput={"ReadCapacityUnits": 5, "WriteCapacityUnits": 5},
    )
    table = ddb.Table('test_table')

    with pytest.raises(botocore.exceptions.ClientError):
        with table.batch_writer() as batch:
            batch.put_item(Item={'value': ''})

Output:

./src/storage/test/test_moto.py::test_batch_put Failed: [undefined]Failed: DID NOT RAISE <class 'botocore.exceptions.ClientError'>
ddb = dynamodb.ServiceResource()

    @mock_dynamodb
    def test_batch_put(ddb):
        ddb.create_table(
            AttributeDefinitions=[{"AttributeName": "value", "AttributeType": "S"}],
            TableName="test_table",
            KeySchema=[{"AttributeName": "value", "KeyType": "HASH"}],
            ProvisionedThroughput={"ReadCapacityUnits": 5, "WriteCapacityUnits": 5},
        )
        table = ddb.Table('test_table')
    
        with pytest.raises(botocore.exceptions.ClientError):
            with table.batch_writer() as batch:
>               batch.put_item(Item={'value': ''})
E               Failed: DID NOT RAISE <class 'botocore.exceptions.ClientError'>

./src/storage/test/test_moto.py:29: Failed

[bblommers]

Thanks for raising this @pawelarybak - marking it as an enhancement to add validation for this use-case