From cac8a660cd7309b238cb0e8e9c2c9bafb56b5cd9 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 01:26:59 +0800
Subject: [PATCH 01/27] move  testSequencer to individual package

---
 packages/jest-core/package.json               |  1 +
 packages/jest-core/src/runJest.ts             |  2 +-
 packages/jest-core/tsconfig.json              |  1 +
 packages/jest-test-sequencer/.npmignore       |  3 +++
 packages/jest-test-sequencer/package.json     | 25 +++++++++++++++++++
 .../src/__tests__/test_sequencer.test.js      |  2 +-
 .../src/index.ts}                             |  4 ++-
 packages/jest-test-sequencer/tsconfig.json    | 13 ++++++++++
 8 files changed, 48 insertions(+), 3 deletions(-)
 create mode 100644 packages/jest-test-sequencer/.npmignore
 create mode 100644 packages/jest-test-sequencer/package.json
 rename packages/{jest-core => jest-test-sequencer}/src/__tests__/test_sequencer.test.js (99%)
 rename packages/{jest-core/src/TestSequencer.ts => jest-test-sequencer/src/index.ts} (98%)
 create mode 100644 packages/jest-test-sequencer/tsconfig.json

diff --git a/packages/jest-core/package.json b/packages/jest-core/package.json
index e9056ba5018c..6e4c673d75ae 100644
--- a/packages/jest-core/package.json
+++ b/packages/jest-core/package.json
@@ -8,6 +8,7 @@
     "@jest/console": "^24.3.0",
     "@jest/reporters": "^24.5.0",
     "@jest/test-result": "^24.5.0",
+    "@jest/test-sequencer": "^24.5.0",
     "@jest/transform": "^24.5.0",
     "@jest/types": "^24.5.0",
     "ansi-escapes": "^3.0.0",
diff --git a/packages/jest-core/src/runJest.ts b/packages/jest-core/src/runJest.ts
index fad2435d8ee0..6386f1e35517 100644
--- a/packages/jest-core/src/runJest.ts
+++ b/packages/jest-core/src/runJest.ts
@@ -25,7 +25,7 @@ import getNoTestsFoundMessage from './getNoTestsFoundMessage';
 import runGlobalHook from './runGlobalHook';
 import SearchSource from './SearchSource';
 import TestScheduler, {TestSchedulerContext} from './TestScheduler';
-import TestSequencer from './TestSequencer';
+import TestSequencer from '@jest/test-sequencer';
 import FailedTestsCache from './FailedTestsCache';
 import collectNodeHandles from './collectHandles';
 import TestWatcher from './TestWatcher';
diff --git a/packages/jest-core/tsconfig.json b/packages/jest-core/tsconfig.json
index 79f9f35b848b..f943dccf39d0 100644
--- a/packages/jest-core/tsconfig.json
+++ b/packages/jest-core/tsconfig.json
@@ -17,6 +17,7 @@
     {"path": "../jest-runtime"},
     {"path": "../jest-snapshot"},
     {"path": "../jest-test-result"},
+    {"path": "../jest-test-sequencer"},
     {"path": "../jest-types"},
     {"path": "../jest-transform"},
     {"path": "../jest-util"},
diff --git a/packages/jest-test-sequencer/.npmignore b/packages/jest-test-sequencer/.npmignore
new file mode 100644
index 000000000000..85e48fe7b0a4
--- /dev/null
+++ b/packages/jest-test-sequencer/.npmignore
@@ -0,0 +1,3 @@
+**/__mocks__/**
+**/__tests__/**
+src
diff --git a/packages/jest-test-sequencer/package.json b/packages/jest-test-sequencer/package.json
new file mode 100644
index 000000000000..69327e50b91b
--- /dev/null
+++ b/packages/jest-test-sequencer/package.json
@@ -0,0 +1,25 @@
+{
+  "name": "@jest/test-sequencer",
+  "version": "24.5.0",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/facebook/jest.git",
+    "directory": "packages/test-sequencer"
+  },
+  "license": "MIT",
+  "main": "build/index.js",
+  "types": "build/index.d.ts",
+  "dependencies": {
+    "@jest/test-result": "^24.5.0",
+    "jest-haste-map": "^24.5.0",
+    "jest-runtime": "^24.5.0",
+    "jest-runner": "^24.5.0"
+  },
+  "engines": {
+    "node": ">= 6"
+  },
+  "publishConfig": {
+    "access": "public"
+  },
+  "gitHead": "800533020f5b2f153615c821ed7cb12fd868fa6f"
+}
diff --git a/packages/jest-core/src/__tests__/test_sequencer.test.js b/packages/jest-test-sequencer/src/__tests__/test_sequencer.test.js
similarity index 99%
rename from packages/jest-core/src/__tests__/test_sequencer.test.js
rename to packages/jest-test-sequencer/src/__tests__/test_sequencer.test.js
index 2e0c8d00f0ea..1252dc1e6e15 100644
--- a/packages/jest-core/src/__tests__/test_sequencer.test.js
+++ b/packages/jest-test-sequencer/src/__tests__/test_sequencer.test.js
@@ -6,7 +6,7 @@
  */
 'use strict';
 
-import TestSequencer from '../TestSequencer';
+import TestSequencer from '../index';
 
 jest.mock('fs');
 
diff --git a/packages/jest-core/src/TestSequencer.ts b/packages/jest-test-sequencer/src/index.ts
similarity index 98%
rename from packages/jest-core/src/TestSequencer.ts
rename to packages/jest-test-sequencer/src/index.ts
index fc1ef479c517..7dc25fde487f 100644
--- a/packages/jest-core/src/TestSequencer.ts
+++ b/packages/jest-test-sequencer/src/index.ts
@@ -31,7 +31,7 @@ type Cache = {
  * TestSequencer.cacheResults(tests: Array<Test>, results: AggregatedResult)
  * is called to store/update this information on the cache map.
  */
-export default class TestSequencer {
+class TestSequencer {
   private _cache: Map<Context, Cache> = new Map();
 
   _getCachePath(context: Context) {
@@ -128,3 +128,5 @@ export default class TestSequencer {
     );
   }
 }
+
+export = TestSequencer;
diff --git a/packages/jest-test-sequencer/tsconfig.json b/packages/jest-test-sequencer/tsconfig.json
new file mode 100644
index 000000000000..78fc3a6be9ed
--- /dev/null
+++ b/packages/jest-test-sequencer/tsconfig.json
@@ -0,0 +1,13 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "build"
+  },
+  "references": [
+    {"path": "../jest-haste-map"},
+    {"path": "../jest-runner"},
+    {"path": "../jest-test-result"},
+    {"path": "../jest-types"}
+  ]
+}

From 27b7ebab888b4a78217c870c19d680d7753b341f Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 01:41:11 +0800
Subject: [PATCH 02/27] add testSequencer option to let user use custom
 sequencer

---
 .../__snapshots__/showConfig.test.ts.snap     |   1 +
 e2e/__tests__/customTestSequencers.test.ts    |  42 ++++++
 e2e/custom-test-sequencer/a.test.js           |   1 +
 e2e/custom-test-sequencer/b.test.js           |   1 +
 e2e/custom-test-sequencer/c.test.js           |   1 +
 e2e/custom-test-sequencer/d.test.js           |   1 +
 e2e/custom-test-sequencer/e.test.js           |   1 +
 e2e/custom-test-sequencer/package.json        |   6 +
 e2e/custom-test-sequencer/testSequencer.js    | 125 ++++++++++++++++++
 packages/jest-cli/src/cli/args.ts             |   7 +
 packages/jest-config/src/Defaults.ts          |   1 +
 packages/jest-config/src/ValidConfig.ts       |   1 +
 packages/jest-config/src/index.ts             |   1 +
 packages/jest-config/src/normalize.ts         |   1 +
 .../jest-core/src/__tests__/run_jest.test.js  |   2 +-
 packages/jest-core/src/runJest.ts             |   3 +-
 packages/jest-types/src/Config.ts             |   4 +
 17 files changed, 197 insertions(+), 2 deletions(-)
 create mode 100644 e2e/__tests__/customTestSequencers.test.ts
 create mode 100644 e2e/custom-test-sequencer/a.test.js
 create mode 100644 e2e/custom-test-sequencer/b.test.js
 create mode 100644 e2e/custom-test-sequencer/c.test.js
 create mode 100644 e2e/custom-test-sequencer/d.test.js
 create mode 100644 e2e/custom-test-sequencer/e.test.js
 create mode 100644 e2e/custom-test-sequencer/package.json
 create mode 100644 e2e/custom-test-sequencer/testSequencer.js

diff --git a/e2e/__tests__/__snapshots__/showConfig.test.ts.snap b/e2e/__tests__/__snapshots__/showConfig.test.ts.snap
index 8b27dc1ba115..44f0f007f29a 100644
--- a/e2e/__tests__/__snapshots__/showConfig.test.ts.snap
+++ b/e2e/__tests__/__snapshots__/showConfig.test.ts.snap
@@ -117,6 +117,7 @@ exports[`--showConfig outputs config info and exits 1`] = `
     "testFailureExitCode": 1,
     "testPathPattern": "",
     "testResultsProcessor": null,
+    "testSequencer": "@jest/test-sequencer",
     "updateSnapshot": "all",
     "useStderr": false,
     "verbose": null,
diff --git a/e2e/__tests__/customTestSequencers.test.ts b/e2e/__tests__/customTestSequencers.test.ts
new file mode 100644
index 000000000000..99fe4b326b5a
--- /dev/null
+++ b/e2e/__tests__/customTestSequencers.test.ts
@@ -0,0 +1,42 @@
+/**
+ * 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 path from 'path';
+import runJest from '../runJest';
+import {extractSummary} from '../Utils';
+const dir = path.resolve(__dirname, '../custom-test-sequencer');
+
+expect.extend({
+  toBeIn(received, arr) {
+    const isIn = arr.includes(received);
+    if (isIn)
+      return {
+        message: `expect ${received} not to be in [${arr.join(', ')}]`,
+        pass: true,
+      };
+    else
+      return {
+        message: `expect ${received} to be in [${arr.join(', ')}]`,
+        pass: false,
+      };
+  },
+});
+
+test('run prioritySequence first', () => {
+  const result = runJest(dir);
+  expect(result.status).toBe(0);
+  const sequence = extractSummary(result.stderr)
+    .rest.replace(/PASS /g, '')
+    .split('\n');
+  expect(sequence).toEqual([
+    './d.test.js',
+    './b.test.js',
+    './c.test.js',
+    expect.toBeIn(['./a.test.js', './e.test.js']),
+    expect.toBeIn(['./a.test.js', './e.test.js']),
+  ]);
+});
diff --git a/e2e/custom-test-sequencer/a.test.js b/e2e/custom-test-sequencer/a.test.js
new file mode 100644
index 000000000000..f624979c394a
--- /dev/null
+++ b/e2e/custom-test-sequencer/a.test.js
@@ -0,0 +1 @@
+test('a', () => {});
diff --git a/e2e/custom-test-sequencer/b.test.js b/e2e/custom-test-sequencer/b.test.js
new file mode 100644
index 000000000000..f809da6a6962
--- /dev/null
+++ b/e2e/custom-test-sequencer/b.test.js
@@ -0,0 +1 @@
+test('b', () => {});
diff --git a/e2e/custom-test-sequencer/c.test.js b/e2e/custom-test-sequencer/c.test.js
new file mode 100644
index 000000000000..cb4854cfb2c9
--- /dev/null
+++ b/e2e/custom-test-sequencer/c.test.js
@@ -0,0 +1 @@
+test('c', () => {});
diff --git a/e2e/custom-test-sequencer/d.test.js b/e2e/custom-test-sequencer/d.test.js
new file mode 100644
index 000000000000..5b88b3563be6
--- /dev/null
+++ b/e2e/custom-test-sequencer/d.test.js
@@ -0,0 +1 @@
+test('d', () => {});
diff --git a/e2e/custom-test-sequencer/e.test.js b/e2e/custom-test-sequencer/e.test.js
new file mode 100644
index 000000000000..a1bc20bfe046
--- /dev/null
+++ b/e2e/custom-test-sequencer/e.test.js
@@ -0,0 +1 @@
+test('e', () => {});
diff --git a/e2e/custom-test-sequencer/package.json b/e2e/custom-test-sequencer/package.json
new file mode 100644
index 000000000000..80ef569e593c
--- /dev/null
+++ b/e2e/custom-test-sequencer/package.json
@@ -0,0 +1,6 @@
+{
+  "jest": {
+    "testEnvironment": "node",
+    "testSequencer": "<rootDir>/testSequencer.js"
+  }
+}
diff --git a/e2e/custom-test-sequencer/testSequencer.js b/e2e/custom-test-sequencer/testSequencer.js
new file mode 100644
index 000000000000..61e1deea40dc
--- /dev/null
+++ b/e2e/custom-test-sequencer/testSequencer.js
@@ -0,0 +1,125 @@
+/**
+ * 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.
+ */
+
+const fs = require('fs');
+const path = require('path');
+const {getCacheFilePath} = require('../../packages/jest-haste-map/build');
+
+const priorityOrder = [
+  path.resolve('./d.test.js'),
+  path.resolve('./b.test.js'),
+  path.resolve('./c.test.js'),
+];
+const FAIL = 0;
+const SUCCESS = 1;
+
+class TestSequencer {
+  constructor() {
+    this._cache = new Map();
+  }
+  _getCachePath(context) {
+    const {config} = context;
+    return getCacheFilePath(config.cacheDirectory, 'perf-cache-' + config.name);
+  }
+
+  _getCache(test) {
+    const {context} = test;
+    if (!this._cache.has(context) && context.config.cache) {
+      const cachePath = this._getCachePath(context);
+      if (fs.existsSync(cachePath)) {
+        try {
+          this._cache.set(
+            context,
+            JSON.parse(fs.readFileSync(cachePath, 'utf8'))
+          );
+        } catch (e) {}
+      }
+    }
+
+    let cache = this._cache.get(context);
+    if (!cache) {
+      cache = {};
+      this._cache.set(context, cache);
+    }
+
+    return 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) {
+    const stats = {};
+    const fileSize = ({path, context: {hasteFS}}) =>
+      stats[path] || (stats[path] = hasteFS.getSize(path) || 0);
+    const hasFailed = (cache, test) =>
+      cache[test.path] && cache[test.path][0] === FAIL;
+    const time = (cache, test) => cache[test.path] && cache[test.path][1];
+
+    tests.forEach(test => (test.duration = time(this._getCache(test), test)));
+    return tests.sort((testA, testB) => {
+      const cacheA = this._getCache(testA);
+      const cacheB = this._getCache(testB);
+      const failedA = hasFailed(cacheA, testA);
+      const failedB = hasFailed(cacheB, testB);
+      const hasTimeA = testA.duration != null;
+      const indexA = priorityOrder.indexOf(testA.path);
+      const indexB = priorityOrder.indexOf(testB.path);
+
+      if (indexA !== indexB) {
+        if (indexA === -1) return 1;
+        if (indexB === -1) return -1;
+        return indexA < indexB ? -1 : 1;
+      } else if (failedA !== failedB) {
+        return failedA ? -1 : 1;
+      } else if (hasTimeA != (testB.duration != null)) {
+        // If only one of two tests has timing information, run it last
+        return hasTimeA ? 1 : -1;
+      } else if (testA.duration != null && testB.duration != null) {
+        return testA.duration < testB.duration ? 1 : -1;
+      } else {
+        return fileSize(testA) < fileSize(testB) ? 1 : -1;
+      }
+    });
+  }
+
+  cacheResults(tests, results) {
+    const map = Object.create(null);
+    tests.forEach(test => (map[test.path] = test));
+    results.testResults.forEach(testResult => {
+      if (testResult && map[testResult.testFilePath] && !testResult.skipped) {
+        const cache = this._getCache(map[testResult.testFilePath]);
+        const perf = testResult.perfStats;
+        cache[testResult.testFilePath] = [
+          testResult.numFailingTests ? FAIL : SUCCESS,
+          perf.end - perf.start || 0,
+        ];
+      }
+    });
+
+    this._cache.forEach((cache, context) =>
+      fs.writeFileSync(this._getCachePath(context), JSON.stringify(cache))
+    );
+  }
+}
+
+module.exports = TestSequencer;
diff --git a/packages/jest-cli/src/cli/args.ts b/packages/jest-cli/src/cli/args.ts
index b98baa1791b1..41bcdc2f5d81 100644
--- a/packages/jest-cli/src/cli/args.ts
+++ b/packages/jest-cli/src/cli/args.ts
@@ -615,6 +615,13 @@ export const options = {
       '`<rootDir>/path/to/testRunner.js`.',
     type: 'string' as 'string',
   },
+  testSequencer: {
+    description:
+      'Allows to specify a custom test sequencer. The default is ' +
+      '`jest-test-sequencer`. A path to a custom test sequencer can be ' +
+      'provided: `<rootDir>/path/to/testSequencer.js`',
+    type: 'string' as 'string',
+  },
   testURL: {
     description: 'This option sets the URL for the jsdom environment.',
     type: 'string' as 'string',
diff --git a/packages/jest-config/src/Defaults.ts b/packages/jest-config/src/Defaults.ts
index 10fed37c6da5..18feac7a11c0 100644
--- a/packages/jest-config/src/Defaults.ts
+++ b/packages/jest-config/src/Defaults.ts
@@ -72,6 +72,7 @@ const defaultOptions: Config.DefaultOptions = {
   testRegex: [],
   testResultsProcessor: null,
   testRunner: 'jasmine2',
+  testSequencer: '@jest/test-sequencer',
   testURL: 'http://localhost',
   timers: 'real',
   transform: null,
diff --git a/packages/jest-config/src/ValidConfig.ts b/packages/jest-config/src/ValidConfig.ts
index fb25df1599bc..544ad1840cd9 100644
--- a/packages/jest-config/src/ValidConfig.ts
+++ b/packages/jest-config/src/ValidConfig.ts
@@ -112,6 +112,7 @@ const initialOptions: Config.InitialOptions = {
   ),
   testResultsProcessor: 'processor-node-module',
   testRunner: 'jasmine2',
+  testSequencer: '@jest/test-sequencer',
   testURL: 'http://localhost',
   timers: 'real',
   transform: {
diff --git a/packages/jest-config/src/index.ts b/packages/jest-config/src/index.ts
index 45bebcafcdac..9f929864554b 100644
--- a/packages/jest-config/src/index.ts
+++ b/packages/jest-config/src/index.ts
@@ -148,6 +148,7 @@ const groupOptions = (
     testNamePattern: options.testNamePattern,
     testPathPattern: options.testPathPattern,
     testResultsProcessor: options.testResultsProcessor,
+    testSequencer: options.testSequencer,
     updateSnapshot: options.updateSnapshot,
     useStderr: options.useStderr,
     verbose: options.verbose,
diff --git a/packages/jest-config/src/normalize.ts b/packages/jest-config/src/normalize.ts
index e43bd523af8a..7bad95fb0d0f 100644
--- a/packages/jest-config/src/normalize.ts
+++ b/packages/jest-config/src/normalize.ts
@@ -571,6 +571,7 @@ export default function normalize(
       case 'snapshotResolver':
       case 'testResultsProcessor':
       case 'testRunner':
+      case 'testSequencer':
       case 'filter':
         {
           const option = oldOptions[key];
diff --git a/packages/jest-core/src/__tests__/run_jest.test.js b/packages/jest-core/src/__tests__/run_jest.test.js
index 3c4c6d170cbc..3293dd4fbcbc 100644
--- a/packages/jest-core/src/__tests__/run_jest.test.js
+++ b/packages/jest-core/src/__tests__/run_jest.test.js
@@ -16,7 +16,7 @@ describe('runJest', () => {
     await runJest({
       changedFilesPromise: Promise.resolve({repos: {git: {size: 0}}}),
       contexts: [],
-      globalConfig: {watch: true},
+      globalConfig: {testSequencer: '@jest/test-sequencer', watch: true},
       onComplete: () => null,
       outputStream: {},
       startRun: {},
diff --git a/packages/jest-core/src/runJest.ts b/packages/jest-core/src/runJest.ts
index 6386f1e35517..c1046afe8567 100644
--- a/packages/jest-core/src/runJest.ts
+++ b/packages/jest-core/src/runJest.ts
@@ -143,7 +143,8 @@ export default (async function runJest({
   failedTestsCache?: FailedTestsCache;
   filter?: Filter;
 }) {
-  const sequencer = new TestSequencer();
+  const Sequencer: typeof TestSequencer = require(globalConfig.testSequencer);
+  const sequencer = new Sequencer();
   let allTests: Array<Test> = [];
 
   if (changedFilesPromise && globalConfig.watch) {
diff --git a/packages/jest-types/src/Config.ts b/packages/jest-types/src/Config.ts
index 76e4d06ef343..f3f4142f1e61 100644
--- a/packages/jest-types/src/Config.ts
+++ b/packages/jest-types/src/Config.ts
@@ -89,6 +89,7 @@ export type DefaultOptions = {
   testRegex: Array<string>;
   testResultsProcessor: string | null | undefined;
   testRunner: string | null | undefined;
+  testSequencer: string;
   testURL: string;
   timers: 'real' | 'fake';
   transform:
@@ -197,6 +198,7 @@ export type InitialOptions = {
   testRegex?: string | Array<string>;
   testResultsProcessor?: string | null | undefined;
   testRunner?: string;
+  testSequencer?: string;
   testURL?: string;
   timers?: 'real' | 'fake';
   transform?: {
@@ -293,6 +295,7 @@ export type GlobalConfig = {
   testNamePattern: string;
   testPathPattern: string;
   testResultsProcessor: string | null | undefined;
+  testSequencer: string;
   updateSnapshot: SnapshotUpdateState;
   useStderr: boolean;
   verbose: boolean | null | undefined;
@@ -436,6 +439,7 @@ export type Argv = Arguments<
     testRegex: string | Array<string>;
     testResultsProcessor: string | null | undefined;
     testRunner: string;
+    testSequencer: string;
     testURL: string;
     timers: string;
     transform: string;

From 4b12436b3811fb69e0a0bfed6fdc9853521bb420 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 02:10:47 +0800
Subject: [PATCH 03/27] giving testSequencer own normalize function

---
 packages/jest-config/src/normalize.ts | 13 ++++++++++++-
 packages/jest-config/src/utils.ts     | 12 ++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/packages/jest-config/src/normalize.ts b/packages/jest-config/src/normalize.ts
index 7bad95fb0d0f..99ec941516f1 100644
--- a/packages/jest-config/src/normalize.ts
+++ b/packages/jest-config/src/normalize.ts
@@ -28,6 +28,7 @@ import {
   getRunner,
   getWatchPlugin,
   resolve,
+  getSequencer,
 } from './utils';
 import {DEFAULT_JS_PATTERN, DEFAULT_REPORTER_LABEL} from './constants';
 import {validateReporters} from './ReporterValidationErrors';
@@ -571,7 +572,6 @@ export default function normalize(
       case 'snapshotResolver':
       case 'testResultsProcessor':
       case 'testRunner':
-      case 'testSequencer':
       case 'filter':
         {
           const option = oldOptions[key];
@@ -595,6 +595,17 @@ export default function normalize(
             });
         }
         break;
+      case 'testSequencer':
+        {
+          const option = oldOptions[key];
+          value =
+            option &&
+            getSequencer(newOptions.resolver, {
+              filePath: option,
+              rootDir: options.rootDir,
+            });
+        }
+        break;
       case 'prettierPath':
         {
           // We only want this to throw if "prettierPath" is explicitly passed
diff --git a/packages/jest-config/src/utils.ts b/packages/jest-config/src/utils.ts
index ca7c5d9d0047..9308f99b6c7d 100644
--- a/packages/jest-config/src/utils.ts
+++ b/packages/jest-config/src/utils.ts
@@ -223,3 +223,15 @@ export const isJSONString = (text?: JSONString | string): text is JSONString =>
   typeof text === 'string' &&
   text.startsWith('{') &&
   text.endsWith('}');
+
+export const getSequencer = (
+  resolver: string | undefined | null,
+  {filePath, rootDir}: {filePath: string; rootDir: Config.Path},
+) =>
+  resolveWithPrefix(resolver, {
+    filePath,
+    humanOptionName: 'Jest Sequencer',
+    optionName: 'sequencer',
+    prefix: 'jest-sequencer-',
+    rootDir,
+  });

From aeea6ade0b10d5c6c32580b343cf7c69c12b684d Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 02:35:13 +0800
Subject: [PATCH 04/27] lint

---
 e2e/custom-test-sequencer/a.test.js | 6 ++++++
 e2e/custom-test-sequencer/b.test.js | 6 ++++++
 e2e/custom-test-sequencer/c.test.js | 6 ++++++
 e2e/custom-test-sequencer/d.test.js | 6 ++++++
 e2e/custom-test-sequencer/e.test.js | 6 ++++++
 packages/jest-core/src/runJest.ts   | 2 +-
 6 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/e2e/custom-test-sequencer/a.test.js b/e2e/custom-test-sequencer/a.test.js
index f624979c394a..1187e8309f87 100644
--- a/e2e/custom-test-sequencer/a.test.js
+++ b/e2e/custom-test-sequencer/a.test.js
@@ -1 +1,7 @@
+/**
+ * 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.
+ */
 test('a', () => {});
diff --git a/e2e/custom-test-sequencer/b.test.js b/e2e/custom-test-sequencer/b.test.js
index f809da6a6962..04e77e777bb1 100644
--- a/e2e/custom-test-sequencer/b.test.js
+++ b/e2e/custom-test-sequencer/b.test.js
@@ -1 +1,7 @@
+/**
+ * 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.
+ */
 test('b', () => {});
diff --git a/e2e/custom-test-sequencer/c.test.js b/e2e/custom-test-sequencer/c.test.js
index cb4854cfb2c9..332d8682ab00 100644
--- a/e2e/custom-test-sequencer/c.test.js
+++ b/e2e/custom-test-sequencer/c.test.js
@@ -1 +1,7 @@
+/**
+ * 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.
+ */
 test('c', () => {});
diff --git a/e2e/custom-test-sequencer/d.test.js b/e2e/custom-test-sequencer/d.test.js
index 5b88b3563be6..4102fe8c1925 100644
--- a/e2e/custom-test-sequencer/d.test.js
+++ b/e2e/custom-test-sequencer/d.test.js
@@ -1 +1,7 @@
+/**
+ * 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.
+ */
 test('d', () => {});
diff --git a/e2e/custom-test-sequencer/e.test.js b/e2e/custom-test-sequencer/e.test.js
index a1bc20bfe046..6b4bbf07b9b4 100644
--- a/e2e/custom-test-sequencer/e.test.js
+++ b/e2e/custom-test-sequencer/e.test.js
@@ -1 +1,7 @@
+/**
+ * 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.
+ */
 test('e', () => {});
diff --git a/packages/jest-core/src/runJest.ts b/packages/jest-core/src/runJest.ts
index c1046afe8567..2123e0a0bc37 100644
--- a/packages/jest-core/src/runJest.ts
+++ b/packages/jest-core/src/runJest.ts
@@ -20,12 +20,12 @@ import {
   AggregatedResult,
   makeEmptyAggregatedTestResult,
 } from '@jest/test-result';
+import TestSequencer from '@jest/test-sequencer';
 import {ChangedFiles, ChangedFilesPromise} from 'jest-changed-files';
 import getNoTestsFoundMessage from './getNoTestsFoundMessage';
 import runGlobalHook from './runGlobalHook';
 import SearchSource from './SearchSource';
 import TestScheduler, {TestSchedulerContext} from './TestScheduler';
-import TestSequencer from '@jest/test-sequencer';
 import FailedTestsCache from './FailedTestsCache';
 import collectNodeHandles from './collectHandles';
 import TestWatcher from './TestWatcher';

From 5093f46cf931d5c939fcea60cfafd17ff0e2b67a Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 10:39:27 +0800
Subject: [PATCH 05/27] remove test comment

---
 e2e/custom-test-sequencer/testSequencer.js | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/e2e/custom-test-sequencer/testSequencer.js b/e2e/custom-test-sequencer/testSequencer.js
index 61e1deea40dc..892e334ba522 100644
--- a/e2e/custom-test-sequencer/testSequencer.js
+++ b/e2e/custom-test-sequencer/testSequencer.js
@@ -49,24 +49,6 @@ class TestSequencer {
     return 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) {
     const stats = {};
     const fileSize = ({path, context: {hasteFS}}) =>

From b94e545785c7bd70b15815b5bde0c04c5d29d434 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 10:40:08 +0800
Subject: [PATCH 06/27] keep export default

---
 packages/jest-test-sequencer/src/index.ts | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/packages/jest-test-sequencer/src/index.ts b/packages/jest-test-sequencer/src/index.ts
index 7dc25fde487f..fc1ef479c517 100644
--- a/packages/jest-test-sequencer/src/index.ts
+++ b/packages/jest-test-sequencer/src/index.ts
@@ -31,7 +31,7 @@ type Cache = {
  * TestSequencer.cacheResults(tests: Array<Test>, results: AggregatedResult)
  * is called to store/update this information on the cache map.
  */
-class TestSequencer {
+export default class TestSequencer {
   private _cache: Map<Context, Cache> = new Map();
 
   _getCachePath(context: Context) {
@@ -128,5 +128,3 @@ class TestSequencer {
     );
   }
 }
-
-export = TestSequencer;

From ca3305e579122aff8c9e111ca6503b1952d18818 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 10:41:21 +0800
Subject: [PATCH 07/27] use interopRequireDefault to import package

---
 packages/jest-core/src/runJest.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/packages/jest-core/src/runJest.ts b/packages/jest-core/src/runJest.ts
index 2123e0a0bc37..ce61fdecbf32 100644
--- a/packages/jest-core/src/runJest.ts
+++ b/packages/jest-core/src/runJest.ts
@@ -9,7 +9,7 @@ import path from 'path';
 import chalk from 'chalk';
 import {sync as realpath} from 'realpath-native';
 import {CustomConsole} from '@jest/console';
-import {formatTestResults} from 'jest-util';
+import {formatTestResults, interopRequireDefault} from 'jest-util';
 import exit from 'exit';
 import fs from 'graceful-fs';
 import {JestHook, JestHookEmitter} from 'jest-watcher';
@@ -143,7 +143,9 @@ export default (async function runJest({
   failedTestsCache?: FailedTestsCache;
   filter?: Filter;
 }) {
-  const Sequencer: typeof TestSequencer = require(globalConfig.testSequencer);
+  const Sequencer: typeof TestSequencer = interopRequireDefault(
+    require(globalConfig.testSequencer),
+  ).default;
   const sequencer = new Sequencer();
   let allTests: Array<Test> = [];
 

From b5c593a668ee170e98fc671084c4b39d515e784e Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 10:41:41 +0800
Subject: [PATCH 08/27] correct `testSequencer` default package name

---
 packages/jest-cli/src/cli/args.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/jest-cli/src/cli/args.ts b/packages/jest-cli/src/cli/args.ts
index 41bcdc2f5d81..4c68b6e1a9c9 100644
--- a/packages/jest-cli/src/cli/args.ts
+++ b/packages/jest-cli/src/cli/args.ts
@@ -618,7 +618,7 @@ export const options = {
   testSequencer: {
     description:
       'Allows to specify a custom test sequencer. The default is ' +
-      '`jest-test-sequencer`. A path to a custom test sequencer can be ' +
+      '`@jest/test-sequencer`. A path to a custom test sequencer can be ' +
       'provided: `<rootDir>/path/to/testSequencer.js`',
     type: 'string' as 'string',
   },

From 92234893d07d3b1ed10c0669484b542cd254693a Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 10:44:26 +0800
Subject: [PATCH 09/27] add runInBand arg to assure running test in sequence

---
 e2e/__tests__/customTestSequencers.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/e2e/__tests__/customTestSequencers.test.ts b/e2e/__tests__/customTestSequencers.test.ts
index 99fe4b326b5a..421b5221368f 100644
--- a/e2e/__tests__/customTestSequencers.test.ts
+++ b/e2e/__tests__/customTestSequencers.test.ts
@@ -27,7 +27,7 @@ expect.extend({
 });
 
 test('run prioritySequence first', () => {
-  const result = runJest(dir);
+  const result = runJest(dir, ['-i']);
   expect(result.status).toBe(0);
   const sequence = extractSummary(result.stderr)
     .rest.replace(/PASS /g, '')

From ec029bbea0313e6dae5f72a0b6f2670c44525b89 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 10:56:59 +0800
Subject: [PATCH 10/27] update changelog

---
 CHANGELOG.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 944c19d56f65..06ecc70dab33 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,11 @@
 - `[jest-runner]` Support default exports for test environments ([#8163](https://github.com/facebook/jest/pull/8163))
 - `[pretty-format]` Support React.Suspense ([#8180](https://github.com/facebook/jest/pull/8180))
 - `[jest-snapshot]` Indent inline snapshots ([#8198](https://github.com/facebook/jest/pull/8198))
+- `[@jest/core]` Move `testSequencer` to individual package `@jest/test-sequencer` ([#8223](https://github.com/facebook/jest/pull/8223))
+- `[@jest/test-sequencer]` Move `testSequencer` to individual package `@jest/test-sequencer` ([#8223](https://github.com/facebook/jest/pull/8223))
+- `[@jest/core]` Add option `testSequencer` allow user use custom sequencer. ([#8223](https://github.com/facebook/jest/pull/8223))
+- `[jest-config]` Add option `testSequencer` allow user use custom sequencer. ([#8223](https://github.com/facebook/jest/pull/8223))
+- `[jest-cli]` Add option `testSequencer` allow user use custom sequencer. ([#8223](https://github.com/facebook/jest/pull/8223))
 
 ### Fixes
 

From 02f14fa3a66e6754179daf0fcc63af3dbb2207cd Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 18:17:22 +0800
Subject: [PATCH 11/27] just only implement sort function in test

---
 e2e/custom-test-sequencer/testSequencer.js | 58 ++--------------------
 1 file changed, 3 insertions(+), 55 deletions(-)

diff --git a/e2e/custom-test-sequencer/testSequencer.js b/e2e/custom-test-sequencer/testSequencer.js
index 892e334ba522..3d3235d4f312 100644
--- a/e2e/custom-test-sequencer/testSequencer.js
+++ b/e2e/custom-test-sequencer/testSequencer.js
@@ -5,9 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-const fs = require('fs');
+const Sequencer = require('@jest/test-sequencer').default;
 const path = require('path');
-const {getCacheFilePath} = require('../../packages/jest-haste-map/build');
 
 const priorityOrder = [
   path.resolve('./d.test.js'),
@@ -15,40 +14,8 @@ const priorityOrder = [
   path.resolve('./c.test.js'),
 ];
 const FAIL = 0;
-const SUCCESS = 1;
-
-class TestSequencer {
-  constructor() {
-    this._cache = new Map();
-  }
-  _getCachePath(context) {
-    const {config} = context;
-    return getCacheFilePath(config.cacheDirectory, 'perf-cache-' + config.name);
-  }
-
-  _getCache(test) {
-    const {context} = test;
-    if (!this._cache.has(context) && context.config.cache) {
-      const cachePath = this._getCachePath(context);
-      if (fs.existsSync(cachePath)) {
-        try {
-          this._cache.set(
-            context,
-            JSON.parse(fs.readFileSync(cachePath, 'utf8'))
-          );
-        } catch (e) {}
-      }
-    }
-
-    let cache = this._cache.get(context);
-    if (!cache) {
-      cache = {};
-      this._cache.set(context, cache);
-    }
-
-    return cache;
-  }
 
+class CustomSequencer extends Sequencer {
   sort(tests) {
     const stats = {};
     const fileSize = ({path, context: {hasteFS}}) =>
@@ -83,25 +50,6 @@ class TestSequencer {
       }
     });
   }
-
-  cacheResults(tests, results) {
-    const map = Object.create(null);
-    tests.forEach(test => (map[test.path] = test));
-    results.testResults.forEach(testResult => {
-      if (testResult && map[testResult.testFilePath] && !testResult.skipped) {
-        const cache = this._getCache(map[testResult.testFilePath]);
-        const perf = testResult.perfStats;
-        cache[testResult.testFilePath] = [
-          testResult.numFailingTests ? FAIL : SUCCESS,
-          perf.end - perf.start || 0,
-        ];
-      }
-    });
-
-    this._cache.forEach((cache, context) =>
-      fs.writeFileSync(this._getCachePath(context), JSON.stringify(cache))
-    );
-  }
 }
 
-module.exports = TestSequencer;
+module.exports = CustomSequencer;

From 46ef8f02c835d3d0f5f711e76d6cbdf61a5e7ff2 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 18:58:40 +0800
Subject: [PATCH 12/27] add a dependency on @jest/test-scheduler to jest-config
 so it works in yarn PnP

---
 packages/jest-config/package.json | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/jest-config/package.json b/packages/jest-config/package.json
index 1ac41fc433f4..0e20f11dd993 100644
--- a/packages/jest-config/package.json
+++ b/packages/jest-config/package.json
@@ -12,6 +12,7 @@
   "dependencies": {
     "@babel/core": "^7.1.0",
     "@jest/types": "^24.5.0",
+    "@jest/test-scheduler": "^24.5.0",
     "babel-jest": "^24.5.0",
     "chalk": "^2.0.1",
     "glob": "^7.1.1",

From 30ac7e5b544ea7e881a811a1c588558c0cc0bf08 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 23:48:17 +0800
Subject: [PATCH 13/27] remove wrong dependency

---
 packages/jest-config/package.json | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/jest-config/package.json b/packages/jest-config/package.json
index 0e20f11dd993..1ac41fc433f4 100644
--- a/packages/jest-config/package.json
+++ b/packages/jest-config/package.json
@@ -12,7 +12,6 @@
   "dependencies": {
     "@babel/core": "^7.1.0",
     "@jest/types": "^24.5.0",
-    "@jest/test-scheduler": "^24.5.0",
     "babel-jest": "^24.5.0",
     "chalk": "^2.0.1",
     "glob": "^7.1.1",

From 4bc5a01ce29285a053b49323b0eaae4422f3c023 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Wed, 27 Mar 2019 23:52:31 +0800
Subject: [PATCH 14/27] let tests easier

---
 e2e/__tests__/customTestSequencers.test.ts | 22 ++----------
 e2e/custom-test-sequencer/testSequencer.js | 42 ++--------------------
 2 files changed, 5 insertions(+), 59 deletions(-)

diff --git a/e2e/__tests__/customTestSequencers.test.ts b/e2e/__tests__/customTestSequencers.test.ts
index 421b5221368f..d9cb5f039db4 100644
--- a/e2e/__tests__/customTestSequencers.test.ts
+++ b/e2e/__tests__/customTestSequencers.test.ts
@@ -10,22 +10,6 @@ import runJest from '../runJest';
 import {extractSummary} from '../Utils';
 const dir = path.resolve(__dirname, '../custom-test-sequencer');
 
-expect.extend({
-  toBeIn(received, arr) {
-    const isIn = arr.includes(received);
-    if (isIn)
-      return {
-        message: `expect ${received} not to be in [${arr.join(', ')}]`,
-        pass: true,
-      };
-    else
-      return {
-        message: `expect ${received} to be in [${arr.join(', ')}]`,
-        pass: false,
-      };
-  },
-});
-
 test('run prioritySequence first', () => {
   const result = runJest(dir, ['-i']);
   expect(result.status).toBe(0);
@@ -33,10 +17,10 @@ test('run prioritySequence first', () => {
     .rest.replace(/PASS /g, '')
     .split('\n');
   expect(sequence).toEqual([
-    './d.test.js',
+    './a.test.js',
     './b.test.js',
     './c.test.js',
-    expect.toBeIn(['./a.test.js', './e.test.js']),
-    expect.toBeIn(['./a.test.js', './e.test.js']),
+    './d.test.js',
+    './e.test.js',
   ]);
 });
diff --git a/e2e/custom-test-sequencer/testSequencer.js b/e2e/custom-test-sequencer/testSequencer.js
index 3d3235d4f312..c4248cf62a6c 100644
--- a/e2e/custom-test-sequencer/testSequencer.js
+++ b/e2e/custom-test-sequencer/testSequencer.js
@@ -6,49 +6,11 @@
  */
 
 const Sequencer = require('@jest/test-sequencer').default;
-const path = require('path');
-
-const priorityOrder = [
-  path.resolve('./d.test.js'),
-  path.resolve('./b.test.js'),
-  path.resolve('./c.test.js'),
-];
-const FAIL = 0;
 
 class CustomSequencer extends Sequencer {
   sort(tests) {
-    const stats = {};
-    const fileSize = ({path, context: {hasteFS}}) =>
-      stats[path] || (stats[path] = hasteFS.getSize(path) || 0);
-    const hasFailed = (cache, test) =>
-      cache[test.path] && cache[test.path][0] === FAIL;
-    const time = (cache, test) => cache[test.path] && cache[test.path][1];
-
-    tests.forEach(test => (test.duration = time(this._getCache(test), test)));
-    return tests.sort((testA, testB) => {
-      const cacheA = this._getCache(testA);
-      const cacheB = this._getCache(testB);
-      const failedA = hasFailed(cacheA, testA);
-      const failedB = hasFailed(cacheB, testB);
-      const hasTimeA = testA.duration != null;
-      const indexA = priorityOrder.indexOf(testA.path);
-      const indexB = priorityOrder.indexOf(testB.path);
-
-      if (indexA !== indexB) {
-        if (indexA === -1) return 1;
-        if (indexB === -1) return -1;
-        return indexA < indexB ? -1 : 1;
-      } else if (failedA !== failedB) {
-        return failedA ? -1 : 1;
-      } else if (hasTimeA != (testB.duration != null)) {
-        // If only one of two tests has timing information, run it last
-        return hasTimeA ? 1 : -1;
-      } else if (testA.duration != null && testB.duration != null) {
-        return testA.duration < testB.duration ? 1 : -1;
-      } else {
-        return fileSize(testA) < fileSize(testB) ? 1 : -1;
-      }
-    });
+    const copyTests = Array.from(tests);
+    return copyTests.sort((testA, testB) => (testA.path > testB.path ? 1 : -1));
   }
 }
 

From 409a9baea5560016c4a906381fa7e1f23e206223 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Thu, 28 Mar 2019 00:32:48 +0800
Subject: [PATCH 15/27] update docs

---
 docs/CLI.md           |  4 ++++
 docs/Configuration.md | 25 +++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/docs/CLI.md b/docs/CLI.md
index 92b7e943441f..858adffdda37 100644
--- a/docs/CLI.md
+++ b/docs/CLI.md
@@ -297,6 +297,10 @@ An array of regexp pattern strings that is tested against all tests paths before
 
 Lets you specify a custom test runner.
 
+### `--testSequencer=<path>`
+
+Lets you specify a custom test sequencer
+
 ### `--updateSnapshot`
 
 Alias: `-u`. Use this flag to re-record every snapshot that fails during this test run. Can be used together with a test suite pattern or with `--testNamePattern` to re-record snapshots.
diff --git a/docs/Configuration.md b/docs/Configuration.md
index 894e840f4b83..b0efae6f4d6f 100644
--- a/docs/Configuration.md
+++ b/docs/Configuration.md
@@ -993,6 +993,31 @@ function testRunner(
 
 An example of such function can be found in our default [jasmine2 test runner package](https://github.com/facebook/jest/blob/master/packages/jest-jasmine2/src/index.js).
 
+### `testSequencer` [string]
+
+Default: `@jest/test-sequencer`
+
+This option allows you to use a custom sequencer instead of Jest's default test runner.
+
+You need to export a sequencer class and set path in the config
+
+
+example:
+
+Sort test path alphabetically 
+```js
+const Sequencer = require('@jest/test-sequencer').default;
+
+class CustomSequencer extends Sequencer {
+  sort(tests) {
+    const copyTests = Array.from(tests);
+    return copyTests.sort((testA, testB) => (testA.path > testB.path ? 1 : -1));
+  }
+}
+
+module.exports = CustomSequencer;
+```
+
 ### `testURL` [string]
 
 Default: `http://localhost`

From abc58e297739385eae3df1919e6839186441a263 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Thu, 28 Mar 2019 00:32:59 +0800
Subject: [PATCH 16/27] fix wrong option name

---
 packages/jest-config/src/utils.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/jest-config/src/utils.ts b/packages/jest-config/src/utils.ts
index 9308f99b6c7d..3cd9f3965a51 100644
--- a/packages/jest-config/src/utils.ts
+++ b/packages/jest-config/src/utils.ts
@@ -231,7 +231,7 @@ export const getSequencer = (
   resolveWithPrefix(resolver, {
     filePath,
     humanOptionName: 'Jest Sequencer',
-    optionName: 'sequencer',
+    optionName: 'testSequencer',
     prefix: 'jest-sequencer-',
     rootDir,
   });

From 934f77cfc3fb692cb5fa37b17aadbc407151ee4d Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Thu, 28 Mar 2019 00:48:13 +0800
Subject: [PATCH 17/27] lint

---
 docs/Configuration.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/Configuration.md b/docs/Configuration.md
index b0efae6f4d6f..aba0ad64aeaa 100644
--- a/docs/Configuration.md
+++ b/docs/Configuration.md
@@ -1001,10 +1001,10 @@ This option allows you to use a custom sequencer instead of Jest's default test
 
 You need to export a sequencer class and set path in the config
 
-
 example:
 
-Sort test path alphabetically 
+Sort test path alphabetically
+
 ```js
 const Sequencer = require('@jest/test-sequencer').default;
 

From 1b3f0ef8f064390ffee55d10450d625837f7a8e1 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Thu, 28 Mar 2019 22:49:01 +0800
Subject: [PATCH 18/27] add Test type in configuration

---
 docs/Configuration.md | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/docs/Configuration.md b/docs/Configuration.md
index aba0ad64aeaa..59a5b9b0efc2 100644
--- a/docs/Configuration.md
+++ b/docs/Configuration.md
@@ -997,11 +997,9 @@ An example of such function can be found in our default [jasmine2 test runner pa
 
 Default: `@jest/test-sequencer`
 
-This option allows you to use a custom sequencer instead of Jest's default test runner.
+This option allows you to use a custom sequencer instead of Jest's default.
 
-You need to export a sequencer class and set path in the config
-
-example:
+Example:
 
 Sort test path alphabetically
 
@@ -1009,7 +1007,9 @@ Sort test path alphabetically
 const Sequencer = require('@jest/test-sequencer').default;
 
 class CustomSequencer extends Sequencer {
-  sort(tests) {
+  sort(tests: Array<Test>) {
+    // Test structure information
+    // https://github.com/facebook/jest/blob/6b8b1404a1d9254e7d5d90a8934087a9c9899dab/packages/jest-runner/src/types.ts#L17-L21
     const copyTests = Array.from(tests);
     return copyTests.sort((testA, testB) => (testA.path > testB.path ? 1 : -1));
   }

From f8b9b17f400d01c409eb09fdefeb05cb6fc19765 Mon Sep 17 00:00:00 2001
From: Tim Seckinger <seckinger.tim@gmail.com>
Date: Sat, 30 Mar 2019 22:24:11 +0800
Subject: [PATCH 19/27] Update docs/CLI.md

Co-Authored-By: WeiAnAn <WeiAnAn@users.noreply.github.com>
---
 docs/CLI.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/CLI.md b/docs/CLI.md
index 858adffdda37..f6b483391f7b 100644
--- a/docs/CLI.md
+++ b/docs/CLI.md
@@ -299,7 +299,7 @@ Lets you specify a custom test runner.
 
 ### `--testSequencer=<path>`
 
-Lets you specify a custom test sequencer
+Lets you specify a custom test sequencer. Please refer to the documentation of the corresponding configuration property for details.
 
 ### `--updateSnapshot`
 

From 4efe85c60771318af3c9e12a6f5163e2636a3d39 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Sat, 30 Mar 2019 23:46:07 +0800
Subject: [PATCH 20/27] keep example as js instead of ts

---
 docs/Configuration.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/Configuration.md b/docs/Configuration.md
index 59a5b9b0efc2..0da42e611a35 100644
--- a/docs/Configuration.md
+++ b/docs/Configuration.md
@@ -1007,7 +1007,7 @@ Sort test path alphabetically
 const Sequencer = require('@jest/test-sequencer').default;
 
 class CustomSequencer extends Sequencer {
-  sort(tests: Array<Test>) {
+  sort(tests) {
     // Test structure information
     // https://github.com/facebook/jest/blob/6b8b1404a1d9254e7d5d90a8934087a9c9899dab/packages/jest-runner/src/types.ts#L17-L21
     const copyTests = Array.from(tests);

From 20910a904ccc13b0212d61baf3b79a5b70d51a7d Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Sat, 30 Mar 2019 23:54:49 +0800
Subject: [PATCH 21/27] update changelog which affect multiple packages to one
 line.

---
 CHANGELOG.md | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 06ecc70dab33..8c85784982b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,11 +9,8 @@
 - `[jest-runner]` Support default exports for test environments ([#8163](https://github.com/facebook/jest/pull/8163))
 - `[pretty-format]` Support React.Suspense ([#8180](https://github.com/facebook/jest/pull/8180))
 - `[jest-snapshot]` Indent inline snapshots ([#8198](https://github.com/facebook/jest/pull/8198))
-- `[@jest/core]` Move `testSequencer` to individual package `@jest/test-sequencer` ([#8223](https://github.com/facebook/jest/pull/8223))
-- `[@jest/test-sequencer]` Move `testSequencer` to individual package `@jest/test-sequencer` ([#8223](https://github.com/facebook/jest/pull/8223))
-- `[@jest/core]` Add option `testSequencer` allow user use custom sequencer. ([#8223](https://github.com/facebook/jest/pull/8223))
-- `[jest-config]` Add option `testSequencer` allow user use custom sequencer. ([#8223](https://github.com/facebook/jest/pull/8223))
-- `[jest-cli]` Add option `testSequencer` allow user use custom sequencer. ([#8223](https://github.com/facebook/jest/pull/8223))
+- `[@jest/core, @jest/test-sequencer]` Move `testSequencer` to individual package `@jest/test-sequencer` ([#8223](https://github.com/facebook/jest/pull/8223))
+- `[jest-config, jest-cli]` Add option `testSequencer` allow user use custom sequencer. ([#8223](https://github.com/facebook/jest/pull/8223))
 
 ### Fixes
 

From 2e8fe7b16c361c7f893804aa33bebba58a036e9a Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Sun, 31 Mar 2019 00:14:00 +0800
Subject: [PATCH 22/27] add @jest/test-sequencer to dependency

---
 packages/jest-config/package.json | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/jest-config/package.json b/packages/jest-config/package.json
index 1ac41fc433f4..cd4052527997 100644
--- a/packages/jest-config/package.json
+++ b/packages/jest-config/package.json
@@ -12,6 +12,7 @@
   "dependencies": {
     "@babel/core": "^7.1.0",
     "@jest/types": "^24.5.0",
+    "@jest/test-sequencer": "^24.5.0",
     "babel-jest": "^24.5.0",
     "chalk": "^2.0.1",
     "glob": "^7.1.1",

From 9662a12e613c949e265ce826c3f2f2b7b44e1aa6 Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Sun, 31 Mar 2019 00:33:16 +0800
Subject: [PATCH 23/27] update changelog

---
 CHANGELOG.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e7a42d8bbcb2..2698161198a2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,7 +11,7 @@
 - `[jest-snapshot]` Indent inline snapshots ([#8198](https://github.com/facebook/jest/pull/8198))
 - `[jest-config]` Support colors in `displayName` configuration ([#8025](https://github.com/facebook/jest/pull/8025))
 - `[@jest/core, @jest/test-sequencer]` Move `testSequencer` to individual package `@jest/test-sequencer` ([#8223](https://github.com/facebook/jest/pull/8223))
-- `[jest-config, jest-cli]` Add option `testSequencer` allow user use custom sequencer. ([#8223](https://github.com/facebook/jest/pull/8223))
+- `[@jest/core, jest-cli, jest-config]` Add option `testSequencer` allow user use custom sequencer. ([#8223](https://github.com/facebook/jest/pull/8223))
 
 ### Fixes
 

From 7e8d15af03f5c2dd29b539ce07fc07a8db492d4e Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Sun, 31 Mar 2019 02:37:42 +0800
Subject: [PATCH 24/27] move @jest/test-sequencer to dev dependency

---
 packages/jest-core/package.json   | 4 ++--
 packages/jest-core/src/runJest.ts | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/jest-core/package.json b/packages/jest-core/package.json
index 6e4c673d75ae..fff8db179a62 100644
--- a/packages/jest-core/package.json
+++ b/packages/jest-core/package.json
@@ -8,7 +8,6 @@
     "@jest/console": "^24.3.0",
     "@jest/reporters": "^24.5.0",
     "@jest/test-result": "^24.5.0",
-    "@jest/test-sequencer": "^24.5.0",
     "@jest/transform": "^24.5.0",
     "@jest/types": "^24.5.0",
     "ansi-escapes": "^3.0.0",
@@ -41,7 +40,8 @@
     "@types/micromatch": "^3.1.0",
     "@types/p-each-series": "^1.0.0",
     "@types/rimraf": "^2.0.2",
-    "@types/strip-ansi": "^3.0.0"
+    "@types/strip-ansi": "^3.0.0",
+    "@jest/test-sequencer": "^24.5.0"
   },
   "engines": {
     "node": ">= 6"
diff --git a/packages/jest-core/src/runJest.ts b/packages/jest-core/src/runJest.ts
index ce61fdecbf32..fd88593d05e4 100644
--- a/packages/jest-core/src/runJest.ts
+++ b/packages/jest-core/src/runJest.ts
@@ -20,7 +20,7 @@ import {
   AggregatedResult,
   makeEmptyAggregatedTestResult,
 } from '@jest/test-result';
-import TestSequencer from '@jest/test-sequencer';
+import TestSequencer from '@jest/test-sequencer'; // eslint-disable-line import/no-extraneous-dependencies
 import {ChangedFiles, ChangedFilesPromise} from 'jest-changed-files';
 import getNoTestsFoundMessage from './getNoTestsFoundMessage';
 import runGlobalHook from './runGlobalHook';

From 0866abad983e9ab1fa8f0ccf7758e457f30244f7 Mon Sep 17 00:00:00 2001
From: Wei An Yen <WeiAnAn@users.noreply.github.com>
Date: Tue, 2 Apr 2019 15:58:22 +0800
Subject: [PATCH 25/27] Update @jest/core package.json

---
 packages/jest-core/package.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/jest-core/package.json b/packages/jest-core/package.json
index fff8db179a62..4393171e59e4 100644
--- a/packages/jest-core/package.json
+++ b/packages/jest-core/package.json
@@ -34,14 +34,14 @@
     "strip-ansi": "^5.0.0"
   },
   "devDependencies": {
+    "@jest/test-sequencer": "^24.5.0",
     "@types/ansi-escapes": "^3.0.1",
     "@types/exit": "^0.1.30",
     "@types/graceful-fs": "^4.1.2",
     "@types/micromatch": "^3.1.0",
     "@types/p-each-series": "^1.0.0",
     "@types/rimraf": "^2.0.2",
-    "@types/strip-ansi": "^3.0.0",
-    "@jest/test-sequencer": "^24.5.0"
+    "@types/strip-ansi": "^3.0.0"
   },
   "engines": {
     "node": ">= 6"

From 745cad3e4038d31a777cbce67d0050c4166d2cda Mon Sep 17 00:00:00 2001
From: Wei An Yen <j22461615@gmail.com>
Date: Tue, 2 Apr 2019 16:06:57 +0800
Subject: [PATCH 26/27] update version to 24.6.0

---
 packages/jest-core/package.json           |  2 +-
 packages/jest-test-sequencer/package.json | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/packages/jest-core/package.json b/packages/jest-core/package.json
index 1fbb3496abbb..34bd6e9e7990 100644
--- a/packages/jest-core/package.json
+++ b/packages/jest-core/package.json
@@ -34,7 +34,7 @@
     "strip-ansi": "^5.0.0"
   },
   "devDependencies": {
-    "@jest/test-sequencer": "^24.5.0",
+    "@jest/test-sequencer": "^24.6.0",
     "@types/ansi-escapes": "^3.0.1",
     "@types/exit": "^0.1.30",
     "@types/graceful-fs": "^4.1.2",
diff --git a/packages/jest-test-sequencer/package.json b/packages/jest-test-sequencer/package.json
index 69327e50b91b..5aad8dca8318 100644
--- a/packages/jest-test-sequencer/package.json
+++ b/packages/jest-test-sequencer/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@jest/test-sequencer",
-  "version": "24.5.0",
+  "version": "24.6.0",
   "repository": {
     "type": "git",
     "url": "https://github.com/facebook/jest.git",
@@ -10,10 +10,10 @@
   "main": "build/index.js",
   "types": "build/index.d.ts",
   "dependencies": {
-    "@jest/test-result": "^24.5.0",
-    "jest-haste-map": "^24.5.0",
-    "jest-runtime": "^24.5.0",
-    "jest-runner": "^24.5.0"
+    "@jest/test-result": "^24.6.0",
+    "jest-haste-map": "^24.6.0",
+    "jest-runtime": "^24.6.0",
+    "jest-runner": "^24.6.0"
   },
   "engines": {
     "node": ">= 6"

From 301a5cda50bf82617fe776938ee3fbd1c24b4a7c Mon Sep 17 00:00:00 2001
From: Simen Bekkhus <sbekkhus91@gmail.com>
Date: Tue, 2 Apr 2019 17:15:41 +0200
Subject: [PATCH 27/27] sort

---
 packages/jest-test-sequencer/package.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/jest-test-sequencer/package.json b/packages/jest-test-sequencer/package.json
index 5aad8dca8318..aec99f7bfab3 100644
--- a/packages/jest-test-sequencer/package.json
+++ b/packages/jest-test-sequencer/package.json
@@ -12,8 +12,8 @@
   "dependencies": {
     "@jest/test-result": "^24.6.0",
     "jest-haste-map": "^24.6.0",
-    "jest-runtime": "^24.6.0",
-    "jest-runner": "^24.6.0"
+    "jest-runner": "^24.6.0",
+    "jest-runtime": "^24.6.0"
   },
   "engines": {
     "node": ">= 6"