def find_passenger_config
      passenger_config = ENV['PASSENGER_CONFIG']
      if passenger_config.nil? || passenger_config.empty?
        passenger_config = find_passenger_config_vendor ||
          find_passenger_config_in_path
      end
      if passenger_config.nil? || passenger_config.empty?
        abort 'ERROR: The unit tests are to be run against a specific ' \
          'Passenger version. However, the \'passenger-config\' command is ' \
          'not found. Please install Passenger, or (if you are sure ' \
          'Passenger is installed) set the PASSENGER_CONFIG environment ' \
          'variable to the \'passenger-config\' command.'
      end
      passenger_config
    end
def find_passenger_config
      passenger_config = ENV['PASSENGER_CONFIG']
      if passenger_config.nil? || passenger_config.empty?
        passenger_config = find_passenger_config_vendor ||
          find_passenger_config_in_path
      end
      if passenger_config.nil? || passenger_config.empty?
        abort 'ERROR: The unit tests are to be run against a specific ' \
          'Passenger version. However, the \'passenger-config\' command is ' \
          'not found. Please install Passenger, or (if you are sure ' \
          'Passenger is installed) set the PASSENGER_CONFIG environment ' \
          'variable to the \'passenger-config\' command.'
      end
      passenger_config
    end
Lookup the `passenger-config` command, either by respecting the
 `PASSENGER_CONFIG` environment variable, or by looking it up in `PATH`.
 If the command cannot be found, the current process aborts with an
 error message.