It's kind of integration tests, so it makes sense to have them, but it will be great to have more thorough specs for each transactional method, like it's done for non-transactional ones:

https://github.com/Dynamoid/dynamoid/blob/master/spec/dynamoid/persistence_spec.rb#L2996-L3037

Such specs would test:

• what actual value of a nullified attribute is persisted (it either has null value or is removed in the item)
• and how store_attribute_with_nil_value option affects this behaviour

I'm thinking to not add tests for store_attribute_with_nil_value = true when there is an index. This fails even without transactions. I suppose I could add a test that a ValidationException is thrown in this case. And that test should exist for both transactions and non-transactions.

  let(:klass_with_gsi) do
    new_class(class_name: 'Ferret') do
      field :name
      field :age, :number
      global_secondary_index hash_key: :name, range_key: :age, projected_attributes: :all, name: 'str_num'
    end
  end
...
    context 'store_attribute_with_nil_value = true', config: { store_attribute_with_nil_value: true } do
      it 'can set gsi field to nil' do
        doc = klass_with_gsi.new
        doc.name = 'abc'
        doc.age = 1
        doc.save!
        doc.age = nil
        doc.save! #      Aws::DynamoDB::Errors::ValidationException: Invalid attribute value type
      end
    end

It seems it's more difficult than just skipping nil values. A nullified attribute of an existing item simply will not be updated at all (so old value will be kept unchanged). So correct logic is to remove such attribute at all.

It's done in the following way in non-transactional method #save:

• https://github.com/Dynamoid/dynamoid/blob/master/lib/dynamoid/persistence/save.rb#L44
• https://github.com/Dynamoid/dynamoid/blob/master/lib/dynamoid/adapter_plugin/aws_sdk_v3/item_updater.rb#L52-L66

Indeed. The code I put in there just skips the nils which is not correct. I'll have to do the removing for all these methods like you said.