Test using ChefDK instead of a the Gemfile. Using gemfiles means you're either constantly working out a set of test deps that work on every platform / ruby version or you're just letting your test deps languish. Use ChefDK and you let Chef worry about the mess that is cross platform ruby deps. You get up to date versions of ChefSpec, Foodcritic, Test Kitchen, etc. This test environment also looks a lot more like a real chef environment with a matching ruby release.
Test using ChefDK instead of a the Gemfile. Using gemfiles means you're either constantly working out a set of test deps that work on every platform / ruby version or you're just letting your test deps languish. Use ChefDK and you let Chef worry about the mess that is cross platform ruby deps. You get up to date versions of ChefSpec, Foodcritic, Test Kitchen, etc. This test environment also looks a lot more like a real chef environment with a matching ruby release.