Rails test: RuntimeError: can't modify frozen String

Question

I'm trying to add my first test to my Rails project and I'm getting an error that I can't figure out.

Everything works fine (I can create articles) normally from the browser, but I'm getting this error in my test:

Test:

  test "should create article" do
    assert_difference('Article.count') do
      post :create, article: {
        title: 'Test Title',
        text: 'This is my first article.',
        status: 'published',
      }, site_id: @site.id
    end
    assert assigns(:article).category_id == nil
    assert_redirected_to site_articles_path(@site)
  end

Running:

[project] rake test
E

Finished in 0.477441s, 2.0945 runs/s, 0.0000 assertions/s.

  1) Error:
ArticlesControllerTest#test_should_create_article:
RuntimeError: can't modify frozen String
    app/controllers/articles_controller.rb:30:in `create'
    test/controllers/articles_controller_test.rb:12:in `block (2 levels) in <class:ArticlesControllerTest>'
    test/controllers/articles_controller_test.rb:11:in `block in <class:ArticlesControllerTest>'

1 runs, 0 assertions, 0 failures, 1 errors, 0 skips

Here's what I think are the relevant parts of the controller:

class ArticlesController < ApplicationController
  before_action :authenticate_user!
  before_action :set_site
  before_action :set_article, only: [:edit, :update, :destroy]

  respond_to :html, :json

  def create
    @article = Article.new(article_params)
    @article.site = @site
    if @article.save
      redirect_to site_articles_path(@site)
    else
      render 'new'
    end
  end

  private
    def set_site
      @site = current_user.sites.find(params[:site_id])
      add_crumb 'Articles', url_for(@site)
    end

    def set_article
      @article = @site.articles.find(params[:id])
    end

    def article_params
      params.require(:article).permit(:title, :text, :status, :category_id, :keywords, :row_order_position)
    end
end

I believe these are the relevant parts of the Model:

class Article < ActiveRecord::Base
  include AlgoliaSearch

  belongs_to :site
  belongs_to :category, counter_cache: true
  validates :site, presence: true
  validates :title, presence: true, length: { minimum: 5 }
  enum status: [ :draft, :published ]

  include RankedModel
  ranks :row_order, :with_same => [:site_id, :category_id]

  algoliasearch per_environment: true, force_utf8_encoding: true, sanitize: true do
    attributes :title, :text, :keywords, :site_id

    removeWordsIfNoResults 'allOptional'

    # Listing attributes in order of priority.
    # Use unordered so we don't boost based on if in beginning of attribute.
    attributesToIndex ['unordered(title)', 'unordered(keywords)', 'unordered(text)']

    attributesToHighlight ['title', 'text']

    tags do
      ["site_#{site.id}", status]
    end
  end

end

Any ideas on why?

Or any suggestions on how to debug this?

Answer 1

I figured it out, turns out it was related to the Algolia tags section in the model. I upgraded algolia-rails package to a newer version and also changed:

["site_#{site.id}", status]

to:

["site_#{site.id}", status.dup]