This isn't all of them, but it makes things look a lot less like:

bundle exec rake test:unit
...
./home/clockwerx/xeroizer/lib/xeroizer/record/base_model.rb:100: warning: instance variable @allow_batch_operations not initialized
/home/clockwerx/xeroizer/lib/xeroizer/record/base_model.rb:100: warning: instance variable @allow_batch_operations not initialized
/home/clockwerx/xeroizer/lib/xeroizer/record/base_model.rb:100: warning: instance variable @allow_batch_operations not initialized
/home/clockwerx/xeroizer/lib/xeroizer/record/base_model.rb:100: warning: instance variable @allow_batch_operations not initialized
/home/clockwerx/xeroizer/lib/xeroizer/record/base_model.rb:100: warning: instance variable @allow_batch_operations not initialized
./home/clockwerx/xeroizer/lib/xeroizer/record/base_model.rb:100: warning: instance variable @allow_batch_operations not initialized
/home/clockwerx/xeroizer/lib/xeroizer/record/base_model.rb:100: warning: instance variable @allow_batch_operations not initialized

Appreciate you fixing these tests. I'm just in the process of making a patch and saw all the warnings 👍

Might need to have a think about the skip_writer or calculated changes; I added documentation but am not really sure if its enough.

It does prevent double method definition though.

Thank you for this pull request @CloCkWeRX. It's so great to see all this work being done on Xeroizer!

It may be easier and quicker for @waynerobinson to review and merge all these changes if you can split this into 3 pull request:

1. warning fixes and similar
2. model/association improvements
3. whitespace changes