ruby-1.9.3-p0 :002 > Factory(:painting).should be_valid
NoMethodError: undefined method `mb_chars' for nil:NilClass
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activesupport-3.1.3/lib/active_support/whiny_nil.rb:48:in `method_missing'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activerecord-3.1.3/lib/active_record/validations/uniqueness.rb:57:in `build_relation'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activerecord-3.1.3/lib/active_record/validations/uniqueness.rb:25:in `validate_each'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activemodel-3.1.3/lib/active_model/validator.rb:153:in `block in validate'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activemodel-3.1.3/lib/active_model/validator.rb:150:in `each'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activemodel-3.1.3/lib/active_model/validator.rb:150:in `validate'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activesupport-3.1.3/lib/active_support/callbacks.rb:302:in `_callback_before_66'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activesupport-3.1.3/lib/active_support/callbacks.rb:449:in `_run_validate_callbacks'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activesupport-3.1.3/lib/active_support/callbacks.rb:81:in `run_callbacks'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activemodel-3.1.3/lib/active_model/validations.rb:212:in `run_validations!'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activemodel-3.1.3/lib/active_model/validations/callbacks.rb:53:in `block in run_validations!'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activesupport-3.1.3/lib/active_support/callbacks.rb:390:in `_run_validation_callbacks'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activesupport-3.1.3/lib/active_support/callbacks.rb:81:in `run_callbacks'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activemodel-3.1.3/lib/active_model/validations/callbacks.rb:53:in `run_validations!'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activemodel-3.1.3/lib/active_model/validations.rb:179:in `valid?'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activerecord-3.1.3/lib/active_record/validations.rb:69:in `valid?'
... 8 levels...
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/activerecord-3.1.3/lib/active_record/transactions.rb:246:in `save!'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/factory_girl-2.3.2/lib/factory_girl/definition.rb:9:in `block in initialize'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/factory_girl-2.3.2/lib/factory_girl/proxy/create.rb:7:in `[]'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/factory_girl-2.3.2/lib/factory_girl/proxy/create.rb:7:in `result'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/factory_girl-2.3.2/lib/factory_girl/factory.rb:163:in `run'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/factory_girl-2.3.2/lib/factory_girl/factory.rb:47:in `run'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/factory_girl-2.3.2/lib/factory_girl/syntax/methods.rb:148:in `run_factory_girl_proxy'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/factory_girl-2.3.2/lib/factory_girl/syntax/methods.rb:63:in `create'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/factory_girl-2.3.2/lib/factory_girl/syntax/vintage.rb:50:in `default_strategy'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/factory_girl-2.3.2/lib/factory_girl/syntax/vintage.rb:143:in `Factory'
        from (irb):2
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/railties-3.1.3/lib/rails/commands/console.rb:45:in `start'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/railties-3.1.3/lib/rails/commands/console.rb:8:in `start'
        from /home/d/.rvm/gems/ruby-1.9.3-p0@lanettes_website/gems/railties-3.1.3/lib/rails/commands.rb:40:in `<top (required)>'
        from script/rails:6:in `require'
        from script/rails:6:in `<main>'r