Wrapping ActiveRecord test causes it to fail (no records found)

Empieza ejecutando la reproducción de Ruby proporcionada con ActiveRecord 4.2.7.1, mysql2, DatabaseCleaner y RSpec; después, compara los ejemplos de text_search y like_search con cada modo de limpieza. Se considera terminado cuando los ejemplos de text_search ya no fallan indicando que no se encontraron registros y el comportamiento de limpieza existente sigue estando cubierto.

I created a script to demonstrate this behavior:

#!/usr/bin/env ruby

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required.  Please update your bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"
  gem "activerecord", "4.2.7.1"
  gem "mysql2", "0.4.5"
  gem "database_cleaner", "1.5.3"
  gem "rspec", "3.5.0"
end

require "active_record"
require "rspec"
require "rspec/autorun"
require "database_cleaner"

ActiveRecord::Base.establish_connection(
  adapter: "mysql2",
  username: "root",
  password: "password",
  host: "localhost",
  database: "ft_test"
)
ActiveRecord::Base.connection.recreate_database "ft_test"

ActiveRecord::Schema.define do
  create_table :widgets, force: true do |t|
    t.string "description", limit: 255
  end

  add_index "widgets", ["description"], name: "widgets_description_fts", type: :fulltext
end

class Widget < ActiveRecord::Base
  def self.text_search(query)
    where("MATCH(description) AGAINST(:query)", query: query)
  end

  def self.like_search(query)
    where("description like ?", "%#{query}%")
  end
end

RSpec.configure do |config|
  config.default_formatter = "doc"
  config.before(:suite) do
    DatabaseCleaner.clean_with(:truncation)
  end
  config.before(:each) do
    DatabaseCleaner.strategy = :transaction
  end
end

RSpec.describe Widget, type: :model do
  describe ".text_search" do
    after(:all) { Widget.delete_all }
    it "fails when cleaning with start/clean" do
      DatabaseCleaner.start

      text_search_test

      DatabaseCleaner.clean
    end

    it "fails when cleaning with block" do
      DatabaseCleaner.cleaning do
        text_search_test
      end
    end

    it "succeeds with manual cleaning (fails at random, unless it is first or the only test run)" do
      Widget.delete_all

      text_search_test

      Widget.delete_all
    end
  end

  describe ".like_search" do
    it "succeeds when cleaning with start/clean" do
      DatabaseCleaner.start

      like_search_test

      DatabaseCleaner.clean
    end

    it "succeeds when cleaning with block" do
      DatabaseCleaner.cleaning do
        like_search_test
      end
    end

    it "succeeds with manual cleaning" do
      Widget.delete_all

      like_search_test

      Widget.delete_all
    end
  end

  private

  def create_widgets
    Widget.create()
    match = Widget.create(description: "The quick brown fox jumps over the lazy dog")
    Widget.create()

    match
  end

  def text_search_test
    match = create_widgets
    expect(Widget.text_search("fox")).to contain_exactly match
  end

  def like_search_test
    match = create_widgets
    expect(Widget.like_search("fox")).to contain_exactly match
  end
end