General comment is this feels like a convolution of test-unit and rspec. I would try and put setup examples closer to the pertinent tests. Further, instead of assert_serialization, I would use a shared example for a serialized object or something and move the stuff in your expectations into a before block in a lot of these specs:

```ruby
it 'does something' do
  before do
    # setup
   end
   
   it_behaves_like 'a serialized object' 
end
```