Drop in test coverage when upgrading from Rails 3.2 to 4.0

I’m in the process of completing a Rails 3.2 to 4.0 migration, I’m using Minitest, FactoryGirl, and SimpleCov in my tests. There was a significant drop in test coverage after the upgrade from 26.2% down 10.7%.

Can anyone shed light on this issue?

Hard to think what might cause this, but I would expect if you compare both coverage reports it should give an indication, e.g. missed files.

@andyw8 - Thanks for the note Andy. It turns out that “config.eager_load” is set to false in /config/environments/test.rb. Setting it to true improves the test coverage. The links below help explain the reasoning behind it.