# File lib/test/unit/fixture.rb, line 140
        def unregister(method_name_or_callback)
          if method_name_or_callback.respond_to?(:call)
            callback = method_name_or_callback
            method_name = callback_method_name(callback)
          else
            method_name = method_name_or_callback
          end
          @unregistered_callbacks << method_name
        end