class ParallelTests::Grouper

def specify_groups(items, num_groups, options, groups)
  specify_test_process_groups = options[:specify_groups].split('|')
  if specify_test_process_groups.count > num_groups
    raise 'Number of processes separated by pipe must be less than or equal to the total number of processes'
  end
  all_specified_tests = specify_test_process_groups.map { |group| group.split(',') }.flatten
  specified_items_found, items = items.partition { |item, _size| all_specified_tests.include?(item) }
  specified_specs_not_found = all_specified_tests - specified_items_found.map(&:first)
  if specified_specs_not_found.any?
    raise "Could not find #{specified_specs_not_found} from --specify-groups in the selected files & folders"
  end
  if specify_test_process_groups.count == num_groups && items.flatten.any?
    raise(
      <<~ERROR
        The number of groups in --specify-groups matches the number of groups from -n but there were other specs
        found in the selected files & folders not specified in --specify-groups. Make sure -n is larger than the
        number of processes in --specify-groups if there are other specs that need to be run. The specs that aren't run:
        #{items.map(&:first)}
      ERROR
    )
  end
  # First order the specify_groups into the main groups array
  specify_test_process_groups.each_with_index do |specify_test_process, i|
    groups[i] = specify_test_process.split(',')
  end
  # Return early when processed specify_groups tests exactly match the items passed in
  return groups if specify_test_process_groups.count == num_groups
  # Now sort the rest of the items into the main groups array
  specified_range = specify_test_process_groups.count..-1
  remaining_groups = groups[specified_range]
  group_features_by_size(items_to_group(items), remaining_groups)
  # Don't sort all the groups, only sort the ones not specified in specify_groups
  sorted_groups = remaining_groups.map { |g| g[:items].sort }
  groups[specified_range] = sorted_groups
  groups
end