test: import some jest tests/examples

.eslintignore

@@ -1 +1,2 @@
+__test__/jest/jest-repo/
 __test__/jest-when/when.test.cjs

.prettierignore

@@ -1,2 +1,3 @@
 pnpm-lock.yaml
+__test__/jest/jest-repo/
 __test__/jest-when/when.test.cjs

__test__/jest/jest-repo/README.md

@@ -0,0 +1,11 @@
+# Jest repo tests
+
+A small subtree of the upstream Jest repo, snapshotted from:
+
+<https://github.com/jestjs/jest/tree/21cce70205025decc778f4aac2ec76051f589fd7>
+
+When updating, use the same commit or update the link and incorporate the changes
+
+## package.json
+
+Do not change, it's needed to make this subtree operate in CJS mode, which jest uses

__test__/jest/jest-repo/examples/expect-extend/__tests__/ranges.test.ts

@@ -0,0 +1,20 @@
+/**
+ * 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.
+ */
+
+import {expect, test} from '@jest/globals';
+import '../toBeWithinRange';
+
+test('is within range', () => expect(100).toBeWithinRange(90, 110));
+
+test('is NOT within range', () => expect(101).not.toBeWithinRange(0, 100));
+
+test('asymmetric ranges', () => {
+  expect({apples: 6, bananas: 3}).toEqual({
+    apples: expect.toBeWithinRange(1, 10),
+    bananas: expect.not.toBeWithinRange(11, 20),
+  });
+});

__test__/jest/jest-repo/examples/expect-extend/toBeWithinRange.ts

@@ -0,0 +1,56 @@
+/**
+ * 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.
+ */
+
+import {expect} from '@jest/globals';
+import type {MatcherFunction} from 'expect';
+
+const toBeWithinRange: MatcherFunction<[floor: unknown, ceiling: unknown]> =
+  function (actual, floor, ceiling) {
+    if (
+      typeof actual !== 'number' ||
+      typeof floor !== 'number' ||
+      typeof ceiling !== 'number'
+    ) {
+      throw new TypeError('These must be of type number!');
+    }
+
+    const pass = actual >= floor && actual <= ceiling;
+    if (pass) {
+      return {
+        message: () =>
+          `expected ${this.utils.printReceived(
+            actual,
+          )} not to be within range ${this.utils.printExpected(
+            `${floor} - ${ceiling}`,
+          )}`,
+        pass: true,
+      };
+    } else {
+      return {
+        message: () =>
+          `expected ${this.utils.printReceived(
+            actual,
+          )} to be within range ${this.utils.printExpected(
+            `${floor} - ${ceiling}`,
+          )}`,
+        pass: false,
+      };
+    }
+  };
+
+expect.extend({
+  toBeWithinRange,
+});
+
+declare module 'expect' {
+  interface AsymmetricMatchers {
+    toBeWithinRange(floor: number, ceiling: number): void;
+  }
+  interface Matchers<R> {
+    toBeWithinRange(floor: number, ceiling: number): R;
+  }
+}

__test__/jest/jest-repo/examples/manual-mocks/__tests__/user.test.js

@@ -0,0 +1,7 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.. All Rights Reserved.
+
+import user from '../models/user';
+
+test('if original user model', () => {
+  expect(user.getAuthenticated()).toEqual({age: 26, name: 'Real name'});
+});

__test__/jest/jest-repo/examples/manual-mocks/models/user.js

@@ -0,0 +1,8 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.. All Rights Reserved.
+
+export default {
+  getAuthenticated: () => ({
+    age: 26,
+    name: 'Real name',
+  }),
+};

__test__/jest/jest-repo/examples/timer/__tests__/infinite_timer_game.test.js

@@ -0,0 +1,30 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.. All Rights Reserved.
+
+'use strict';
+
+jest.useFakeTimers();
+
+it('schedules a 10-second timer after 1 second', () => {
+  jest.spyOn(globalThis, 'setTimeout');
+  const infiniteTimerGame = require('../infiniteTimerGame');
+  const callback = jest.fn();
+
+  infiniteTimerGame(callback);
+
+  // At this point in time, there should have been a single call to
+  // setTimeout to schedule the end of the game in 1 second.
+  expect(setTimeout).toHaveBeenCalledTimes(1);
+  expect(setTimeout).toHaveBeenNthCalledWith(1, expect.any(Function), 1000);
+
+  // Fast forward and exhaust only currently pending timers
+  // (but not any new timers that get created during that process)
+  jest.runOnlyPendingTimers();
+
+  // At this point, our 1-second timer should have fired its callback
+  expect(callback).toHaveBeenCalled();
+
+  // And it should have created a new timer to start the game over in
+  // 10 seconds
+  expect(setTimeout).toHaveBeenCalledTimes(2);
+  expect(setTimeout).toHaveBeenNthCalledWith(2, expect.any(Function), 10_000);
+});

__test__/jest/jest-repo/examples/timer/__tests__/timer_game.test.js

@@ -0,0 +1,52 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.. All Rights Reserved.
+
+'use strict';
+
+jest.useFakeTimers();
+
+describe('timerGame', () => {
+  beforeEach(() => {
+    jest.spyOn(globalThis, 'setTimeout');
+  });
+  it('waits 1 second before ending the game', () => {
+    const timerGame = require('../timerGame');
+    timerGame();
+
+    expect(setTimeout).toHaveBeenCalledTimes(1);
+    expect(setTimeout).toHaveBeenCalledWith(expect.any(Function), 1000);
+  });
+
+  it('calls the callback after 1 second via runAllTimers', () => {
+    const timerGame = require('../timerGame');
+    const callback = jest.fn();
+
+    timerGame(callback);
+
+    // At this point in time, the callback should not have been called yet
+    expect(callback).not.toHaveBeenCalled();
+
+    // Fast-forward until all timers have been executed
+    jest.runAllTimers();
+
+    // Now our callback should have been called!
+    expect(callback).toHaveBeenCalled();
+    expect(callback).toHaveBeenCalledTimes(1);
+  });
+
+  it('calls the callback after 1 second via advanceTimersByTime', () => {
+    const timerGame = require('../timerGame');
+    const callback = jest.fn();
+
+    timerGame(callback);
+
+    // At this point in time, the callback should not have been called yet
+    expect(callback).not.toHaveBeenCalled();
+
+    // Fast-forward until all timers have been executed
+    jest.advanceTimersByTime(1000);
+
+    // Now our callback should have been called!
+    expect(callback).toHaveBeenCalled();
+    expect(callback).toHaveBeenCalledTimes(1);
+  });
+});

__test__/jest/jest-repo/examples/timer/infiniteTimerGame.js

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+// Copyright (c) Meta Platforms, Inc. and affiliates.. All Rights Reserved.
+
+function infiniteTimerGame(callback) {
+  console.log('Ready....go!');
+
+  setTimeout(() => {
+    console.log('Times up! 10 seconds before the next game starts...');
+    callback && callback();
+
+    // Schedule the next game in 10 seconds
+    setTimeout(() => {
+      infiniteTimerGame(callback);
+    }, 10_000);
+  }, 1000);
+}
+
+module.exports = infiniteTimerGame;

__test__/jest/jest-repo/examples/timer/timerGame.js

@@ -0,0 +1,11 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.. All Rights Reserved.
+
+function timerGame(callback) {
+  console.log('Ready....go!');
+  setTimeout(() => {
+    console.log('Times up -- stop!');
+    callback && callback();
+  }, 1000);
+}
+
+module.exports = timerGame;

__test__/jest/jest-repo/examples/typescript/__tests__/sum.test.js

@@ -0,0 +1,13 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.. All Rights Reserved.
+
+import {expect, it} from '@jest/globals';
+
+it('adds 1 + 2 to equal 3 in Typescript', () => {
+  const sum = require('../sum.ts').default;
+  expect(sum(1, 2)).toBe(3);
+});
+
+it('adds 1 + 2 to equal 3 in JavaScript', () => {
+  const sum = require('../sum.js');
+  expect(sum(1, 2)).toBe(3);
+});

__test__/jest/jest-repo/examples/typescript/sum.js

@@ -0,0 +1,7 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.. All Rights Reserved.
+
+function sum(a, b) {
+  return a + b;
+}
+
+module.exports = sum;

__test__/jest/jest-repo/examples/typescript/sum.ts

@@ -0,0 +1,5 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.
+
+const sum = (a: number, b: number): number => a + b;
+
+export default sum;

__test__/jest/jest-repo/package.json

@@ -0,0 +1 @@
+{ "type": "commonjs" }

package.json

@@ -59,6 +59,7 @@
   "devDependencies": {
     "@exodus/eslint-config": "^5.24.0",
     "@exodus/prettier": "^1.0.0",
+    "@jest/globals": "^29.7.0",
     "@types/jest-when": "^3.5.2",
     "@typescript-eslint/eslint-plugin": "^7.15.0",
     "eslint": "^8.44.0",