@jest/core/build/testSchedulerHelper.js

'use strict';

Object.defineProperty(exports, '__esModule', {
  value: true
});
exports.shouldRunInBand = shouldRunInBand;
/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

const SLOW_TEST_TIME = 1000;
function shouldRunInBand(
  tests,
  timings,
  {
    detectOpenHandles,
    maxWorkers,
    runInBand,
    watch,
    watchAll,
    workerIdleMemoryLimit
  }
) {
  // If user asked for run in band, respect that.
  // detectOpenHandles makes no sense without runInBand, because it cannot detect leaks in workers
  if (runInBand || detectOpenHandles) {
    return true;
  }

  /*
   * If we are using watch/watchAll mode, don't schedule anything in the main
   * thread to keep the TTY responsive and to prevent watch mode crashes caused
   * by leaks (improper test teardown).
   */
  if (watch || watchAll) {
    return false;
  }

  /*
   * Otherwise, run in band if we only have one test or one worker available.
   * Also, if we are confident from previous runs that the tests will finish
   * quickly we also run in band to reduce the overhead of spawning workers.
   */
  const areFastTests = timings.every(timing => timing < SLOW_TEST_TIME);
  const oneWorkerOrLess = maxWorkers <= 1;
  const oneTestOrLess = tests.length <= 1;
  return (
    // When specifying a memory limit, workers should be used
    !workerIdleMemoryLimit &&
    (oneWorkerOrLess ||
      oneTestOrLess ||
      (tests.length <= 20 && timings.length > 0 && areFastTests))
  );
}