```ruby
describe 'transformer_key_to_s' do
  moneta_build do
    Moneta.build do
      use :Transformer, key: :to_s
      adapter :Memory
    end
  end

  moneta_loader{ |value| value }

  moneta_specs TRANSFORMER_SPECS.returnsame.simplekeys_only

  it 'compile transformer class' do
    store.should_not be_nil
    Moneta::Transformer::To_sKey.should_not be_nil
  end
end
```

Fix for :to_s transformer class name
user
```ruby
describe 'transformer_key_to_s' do
  moneta_build do
    Moneta.build do
      use :Transformer, key: :to_s
      adapter :Memory
    end
  end

  moneta_loader{ |value| value }

  moneta_specs TRANSFORMER_SPECS.returnsame.simplekeys_only

  it 'compile transformer class' do
    store.should_not be_nil
    Moneta::Transformer::ToSKey.should_not be_nil
  end
end
```
assistant