Ruby on Rails

While working on a Rails app recently, I stumbled across a frustrating bug that only appeared in the test environment. Everything worked perfectly in the development console. Models loaded fine. Associations were intact. My concern methods behaved exactly as expected. But then my test suite started throwing mysterious NoMethodErrors—complaining that an ActiveRecord model was missing associations it clearly had.

Alberto Fortin’s recent post on dialing back LLM usage resonated with me. Like many developers, I’ve found AI to be both a productivity godsend and a source of friction. It can feel like magic — until it quietly leads you down the wrong path.

If you’ve ever encountered a situation where your Rails model associations work perfectly in the console but mysteriously fail in your test suite, you’re not alone. I recently ran into this exact issue and wanted to share the solution along with some insights about Rails’ autoloading behavior.