• Version 28.1.0
  • Published
  • 13.2 kB
  • 4 dependencies
  • MIT license


npm i @jest/test-sequencer
yarn add @jest/test-sequencer
pnpm add @jest/test-sequencer


Overview not available.



class TestSequencer

class TestSequencer {}
  • 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) to sort the order of the provided tests.

    After the results are collected, TestSequencer.cacheResults(tests: Array, results: AggregatedResult) is called to store/update this information on the cache map.

method allFailedTests

allFailedTests: (tests: Array<Test>) => Array<Test> | Promise<Array<Test>>;

    method cacheResults

    cacheResults: (tests: Array<Test>, results: AggregatedResult) => void;

      method shard

      shard: (
      tests: Array<Test>,
      options: ShardOptions
      ) => Array<Test> | Promise<Array<Test>>;
      • Select tests for shard requested via --shard=shardIndex/shardCount Sharding is applied before sorting

        Parameter tests

        All tests

        Parameter options

        shardIndex and shardIndex to select

        Example 1

        class CustomSequencer extends Sequencer {
        shard(tests, { shardIndex, shardCount }) {
        const shardSize = Math.ceil(tests.length / options.shardCount);
        const shardStart = shardSize * (options.shardIndex - 1);
        const shardEnd = shardSize * options.shardIndex;
        return [...tests]
        .sort((a, b) => (a.path > b.path ? 1 : -1))
        .slice(shardStart, shardEnd);

      method sort

      sort: (tests: Array<Test>) => Array<Test> | Promise<Array<Test>>;
      • Sort test to determine order of execution Sorting is applied after sharding

        Parameter tests

        class CustomSequencer extends Sequencer {
        sort(tests) {
        const copyTests = Array.from(tests);
        return [...tests].sort((a, b) => (a.path > b.path ? 1 : -1));

      Type Aliases

      type ShardOptions

      type ShardOptions = {
      shardIndex: number;
      shardCount: number;

        Package Files (1)

        Dependencies (4)

        Dev Dependencies (2)

        Peer Dependencies (0)

        No peer dependencies.


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