call

# File activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb, line 354
      def call(env)
        @app.call(env)
      ensure
        # Don't return connection (and perform implicit rollback) if
        # this request is a part of integration test
        unless env.key?("rack.test")
          ActiveRecord::Base.clear_active_connections!
        end
      end