config_test.rb

# frozen_string_literal: true

require "test_helper"
require "diffy"
require "rubocop"
require "rake"

class ConfigTest < Minitest::Test
  FULL_CONFIG_PATH = "test/fixtures/full_config.yml"

  def test_config_is_unchanged
    skip if checking_rubocop_version_compatibility?

    Rake.application.load_rakefile

    original_config = FULL_CONFIG_PATH

    Tempfile.create do |tempfile|
      Rake::Task["config:dump"].invoke(tempfile.path)

      diff = Diffy::Diff.new(
        original_config, tempfile.path, source: "files", context: 5
      ).to_s

      error_message = <<~ERROR
        Error: unexpected RuboCop configuration changes were detected.

        #{diff}

        If these changes are intentional, please update the config dump
        by running `bundle exec rake config:dump`.
      ERROR

      assert(diff.empty?, error_message)
    end
  end

  def test_config_has_no_redundant_entries
    skip if checking_rubocop_version_compatibility?

    config = RuboCop::ConfigLoader.load_file("rubocop.yml")
    default_config = RuboCop::ConfigLoader.default_configuration
    redundant_config = Hash.new { |hash, key| hash[key] = {} }

    # This entry is not a cop.
    config.delete("inherit_mode")

    config.each do |cop_name, cop_config|
      default_cop_config = default_config.fetch(cop_name)
      cop_config.each do |key, value|
        default_value = default_cop_config[key]
        redundant_config[cop_name][key] = value if value == default_value
      end
    end

    error_message = <<~ERROR
      Error: The following config values are the same as the default Rubocop configuration:

      #{redundant_config.to_yaml.delete_prefix("---\n")}

      Please remove these entries from the configuration, as they are unnecessary.
    ERROR

    assert(redundant_config.empty?, error_message)
  end

  def test_config_is_sorted_alphabetically
    config_keys = RuboCop::ConfigLoader.load_file("rubocop.yml").to_hash.keys
    all_cops_index = config_keys.index("AllCops")
    following_keys = config_keys[(all_cops_index + 1)..-1]

    assert_sorted(following_keys, "Keys after AllCops in rubocop.yml must be sorted")
  end

  def test_no_cops_are_configured_as_pending
    pending_cops = []

    YAML.unsafe_load_file(FULL_CONFIG_PATH).each do |cop_name, cop_config|
      pending_cops << cop_name if Hash === cop_config && cop_config["Enabled"] == "pending"
    end

    assert(pending_cops.empty?, <<~ERROR_MESSAGE.chomp)
      Error: The style guide should take a stance on all cops, but following cops are marked as pending:

      #{pending_cops.map { "    #{_1}:\n      Enabled: pending" }.join("\n\n")}

      Please update the config to mark all of the these cops as either `Enabled: true` or `Enabled: false`

      If this is a bad time to triage, please open an issue, and mark them as `Enabled: false` for now.
    ERROR_MESSAGE
  end

  def test_config_does_not_check_for_rubocop_versions_below_minimum_version
    rubocop_version_requirement = Gem
      .loaded_specs.fetch('rubocop-shopify')
      .dependencies.find { _1.name == 'rubocop' }
      .requirement

    # RuboCop version checks are done in ERB, so we need to read the raw file
    redundant_rubocop_version_checks = File.read('rubocop.yml').each_line.with_index.filter_map do |line, index|
      match = line.match(/<% if rubocop_version >= "(?<version>.*)" %>/)
      next unless match

      minimum_version_for_config = Gem::Version.new(match[1])
      next if rubocop_version_requirement.satisfied_by?(minimum_version_for_config)

      [index, line.chomp]
    end

    assert(redundant_rubocop_version_checks.empty?, <<~ERROR_MESSAGE.chomp)
      The following RuboCop version check(s) are redundant given the gemspec's version requirement (#{rubocop_version_requirement}):

      #{redundant_rubocop_version_checks.map { "    #{_1.to_s.rjust(4)}: #{_2}" }.join("\n")}

      Please remove these check(s), or (if you intend to maintain compatibility) loosen the `rubocop` requirement in the gemspec.
    ERROR_MESSAGE
  end

  private

  def checking_rubocop_version_compatibility?
    ENV.fetch("CHECKING_RUBOCOP_VERSION_COMPATIBILITY", "") == "true"
  end

  def assert_sorted(actual, message)
    expected_string = actual.sort.join("\n")
    actual_string = actual.join("\n")

    assert_equal(expected_string, actual_string, message)
  end
end