index.d.ts 2.08 KB
/**
 * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
import type { AggregatedResult } from '@jest/test-result';
import type { Test } from 'jest-runner';
import type { Context } from 'jest-runtime';
declare type Cache = {
    [key: string]: [0 | 1, number];
};
/**
 * The TestSequencer will ultimately decide which tests should run first.
 * It is responsible for storing and reading from a local cache
 * map that stores context information for a given test, such as how long it
 * took to run during the last run and if it has failed or not.
 * Such information is used on:
 * TestSequencer.sort(tests: Array<Test>)
 * to sort the order of the provided tests.
 *
 * After the results are collected,
 * TestSequencer.cacheResults(tests: Array<Test>, results: AggregatedResult)
 * is called to store/update this information on the cache map.
 */
export default class TestSequencer {
    private _cache;
    _getCachePath(context: Context): string;
    _getCache(test: Test): Cache;
    /**
     * Sorting tests is very important because it has a great impact on the
     * user-perceived responsiveness and speed of the test run.
     *
     * If such information is on cache, tests are sorted based on:
     * -> Has it failed during the last run ?
     * Since it's important to provide the most expected feedback as quickly
     * as possible.
     * -> How long it took to run ?
     * Because running long tests first is an effort to minimize worker idle
     * time at the end of a long test run.
     * And if that information is not available they are sorted based on file size
     * since big test files usually take longer to complete.
     *
     * Note that a possible improvement would be to analyse other information
     * from the file other than its size.
     *
     */
    sort(tests: Array<Test>): Array<Test>;
    allFailedTests(tests: Array<Test>): Array<Test>;
    cacheResults(tests: Array<Test>, results: AggregatedResult): void;
}
export {};