Rails 4 Tests running in "development" environment by default

We are porting a Rails 3 project to Rails 4. Our tests run fine under Rails 3, environment is correctly defaulted to test. However, when I switch over to my Rails 4 project and run the tests the same way...

rake test:controllers

My tests are running under development environment, wipes my dev db and output goes to development.log. I can not figure out the difference.

In my test_helper.rb I have this line...

ENV["RAILS_ENV"] = "test"

I've even tried...

Rails.env = "test"

and that does not work either.

Strange thing is, I have these puts in my test...

puts "#{__method__} Rails.env:       #{Rails.env}"
puts "#{__method__} ENV[RAILS_ENV]:  #{ENV["RAILS_ENV"]}"

and they both correctly show that I am in the "test" environment.

If I prefix RAILS_ENV=test before the rake test:controllers, all is well, but I should not have to do that.

Thank you