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


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require "cases/helper"
require "models/developer"
require "models/computer"

class Mysql2ExplainTest < ActiveRecord::Mysql2TestCase
  fixtures :developers

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

  def test_explain_with_eager_loading
    explain = Developer.where(id: 1).includes(:audit_logs).explain
    assert_match %(EXPLAIN for: SELECT `developers`.* FROM `developers` WHERE `developers`.`id` = 1), explain
    assert_match %r(developers |.* const), explain
    assert_match %(EXPLAIN for: SELECT `audit_logs`.* FROM `audit_logs` WHERE `audit_logs`.`developer_id` = 1), explain
    assert_match %r(audit_logs |.* ALL), explain
  end
end