require 'abstract_unit' require 'action_controller/metal/strong_parameters' class ParametersDupTest < ActiveSupport::TestCase setup do ActionController::Parameters.permit_all_parameters = false @params = ActionController::Parameters.new( person: { age: '32', name: { first: 'David', last: 'Heinemeier Hansson' }, addresses: [{city: 'Chicago', state: 'Illinois'}] } ) end test "changes on a duplicate do not affect the original" do dupped_params = @params.dup dupped_params.delete(:person) assert_not_equal @params, dupped_params end end