Recently integrated a patch for strong_parameters into a fork of
active_admin and wanted to add tests for it, but I'm not sure what the best
way of adding tests is for something that can optionally support
strong_parameters.

For those that are trying to write tests that support controller
functionality with and without strong_parameters in their gem, how do you
do that? (I guess this question will apply to those wanting to support both
rails 3 and 4 in a gem and be able to test controller additions without
having to have a separate fork for rails 4).

Is there a switch for enabling and disabling strong_parameters such that it
could be disabled and then just enable it for a single test?

Just wanted to follow-up on this thread, even though it was answered in
another.

A feature addition to disable SP, somewhat similar to how whitelisting was
enabled/disabled in Rails 3 was turned down (who knows- maybe that will be
reconsidered at some point, but dhh said no). But for SP, in your tests
that use Rails 3.2, you may just be able to have models that and some that
don't include ActiveModel::ForbiddenAttributesProtection:
include ::ActiveModel::ForbiddenAttributesProtection

or something that was suggested was to use the appraisal gem:
https://github.com/thoughtbot/appraisal

And some projects like ActiveAdmin also have their own method to test with
different gemsets by including logic in the Gemfile, e.g. in v0.5.0's
Gemfile (in https://github.com/gregbell/active_admin/tree/v0.5.0):

ACTIVE_ADMIN_PATH = File.dirname(__FILE__) unless defined?(ACTIVE_ADMIN_PATH)

require File.expand_path('spec/support/detect_rails_version', ACTIVE_ADMIN_PATH)

rails_version = detect_rails_version
gem 'rails',          rails_version
#...

case rails_version
when /^3\.0/
  # Do nothing, bundler should figure it out
when /^3\.(1|2)/
  # These are the gems you have to have for Rails 3.1 to be happy
  gem 'sass-rails'
  gem 'uglifier'
else
  raise "Rails #{rails_version} is not supported yet"
end