You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: best_index_test.rb
    path of file: ./repos/pghero/test
    
    the code of the file until where you have to start completion: require_relative "test_helper"

class BestIndexTest < Minitest::Test
  def test_where
    assert_best_index ({table: "users", columns: ["city_id"]}), "SELECT * FROM users WHERE city_id = 1"
  end

  def test_all_values
    index = database.best_index("SELECT * FROM users WHERE login_attempts = 1 ORDER BY created_at")
    expected = {
      found: true,
      structure: {table: "
    
  def test_all_values
    index = database.best_index("SELECT * FROM users WHERE login_attempts = 1 ORDER BY created_at")
    expected = {
      found: true,
      structure: {table: "users", where: [{column: "login_attempts", op: "="}], sort: [{column: "created_at", direction: "asc"}]},
      index: {table: "users", columns: ["login_attempts", "created_at"]},
      rows: 5000,
      row_estimates: {"login_attempts (=)" => 167, "created_at (sort)" => 1},
      row_progression: [5000, 167, 0]
    }
    assert_equal expected, index
  end