# File test/test_params.rb, line 1617
    def test_argument_text
      init_arguments
      assert_equal('<html>Hello world.</html>', @entry.args[2])
      @entry.set_arg_at(2, 'Hello world.')
      assert_equal('Hello world.', @entry.args[2])
      @entry.set_arg_at(2, nil) # allowed
      assert_exception(RuntimeError) {
        @entry.set_arg_at(2, :Hello_world) # not allowed
      }
    end