scrub_env!

# File actionpack/lib/action_controller/test_case.rb, line 598
        def scrub_env!(env)
          env.delete_if { |k, v| k =~ /^(action_dispatch|rack)\.request/ }
          env.delete_if { |k, v| k =~ /^action_dispatch\.rescue/ }
          env.delete "action_dispatch.request.query_parameters"
          env.delete "action_dispatch.request.request_parameters"
          env["rack.input"] = StringIO.new
          env
        end