在Michael Hartl（出色的）Rails教程的第7章，练习2

Question

练习2：他建议的用于检查与表单注册相关的错误消息的模板是下面的最后两个assert_selects：

require 'test_helper'

class UsersSignupTest < ActionDispatch::IntegrationTest

  test "invalid signup information" do
    get signup_path
    assert_no_difference 'User.count' do
      post users_path, user: { name:  "",
                               email: "user@invalid",
                               password:              "foo",
                               password_confirmation: "bar" }
    end
    assert_template 'users/new'
    assert_select 'div#<CSS id for error explanation>'
    assert_select 'div.<CSS class for field with error>'
  end

我无法弄清楚需要用什么来代替他在括号内的内容。 自定义CSS的表单部分如下所示：

#error_explanation {
  color: red;
  ul {
    color: red;
    margin: 0 0 30px 0;
  }
}

.field_with_errors {
  @extend .has-error;
  .form-control {
    color: $state-danger-text;
  }
}

Answer 1

按照他的指示添加它们

  assert_select 'div#<CSS id for error explanation>'
  assert_select 'div.<CSS class for field with error>'

将会

  assert_select 'div#error_explanation'
  assert_select 'div.field_with_errors'

Answer 2

assert_select 'div#error_explanation'
assert_select 'div.field_with_errors'

本教程希望我用上述代码替换示例。 我不明白，但终于找到了答案。