activerecord/test/cases/adapters/mysql2/explain_test.rb


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# frozen_string_literal: true

require "cases/helper"
require "models/author"
require "models/post"

class Mysql2ExplainTest < ActiveRecord::Mysql2TestCase
  fixtures :authors

  def test_explain_for_one_query
    explain = Author.where(id: 1).explain
    assert_match %(EXPLAIN for: SELECT `authors`.* FROM `authors` WHERE `authors`.`id` = 1), explain
    assert_match %r(authors |.* const), explain
  end

  def test_explain_with_eager_loading
    explain = Author.where(id: 1).includes(:posts).explain
    assert_match %(EXPLAIN for: SELECT `authors`.* FROM `authors` WHERE `authors`.`id` = 1), explain
    assert_match %r(authors |.* const), explain
    assert_match %(EXPLAIN for: SELECT `posts`.* FROM `posts` WHERE `posts`.`author_id` = 1), explain
    assert_match %r(posts |.* ALL), explain
  end
end