class ParallelTests::Test::Runner

def execute_command(cmd, process_number, num_processes, options)
  env = (options[:env] || {}).merge(
    "TEST_ENV_NUMBER" => test_env_number(process_number, options),
    "PARALLEL_TEST_GROUPS" => num_processes
  )
  cmd = "nice #{cmd}" if options[:nice]
  cmd = "#{cmd} 2>&1" if options[:combine_stderr]
  cmd = ParallelTests.with_ruby_binary(cmd)
  puts cmd if options[:verbose]
  execute_command_and_capture_output(env, cmd, options[:serialize_stdout])
end