Blame · testUtils.ts

b69ab31	1	/**
b69ab31	2	* Copyright (c) Meta Platforms, Inc. and affiliates.
b69ab31	3	*
b69ab31	4	* This source code is licensed under the MIT license found in the
b69ab31	5	* LICENSE file in the root directory of this source tree.
b69ab31	6	*/
b69ab31	7
b69ab31	8	import type {MeasureMemoryOptions} from 'node:vm';
b69ab31	9	import type {Json} from './typeUtils';
b69ab31	10
b69ab31	11	import {measureMemory} from 'node:vm';
b69ab31	12	import {Logger} from '../isl-server/src/logger';
b69ab31	13
b69ab31	14	export class MockLogger extends Logger {
b69ab31	15	write() {
b69ab31	16	// noop
b69ab31	17	}
b69ab31	18	}
b69ab31	19	export const mockLogger = new MockLogger();
b69ab31	20
b69ab31	21	export function clone<T extends Json>(o: T): T {
b69ab31	22	return JSON.parse(JSON.stringify(o));
b69ab31	23	}
b69ab31	24
b69ab31	25	/**
b69ab31	26	* Returns a Promise which resolves after the current async tick is finished.
b69ab31	27	* Useful for testing code which `await`s.
b69ab31	28	*/
b69ab31	29	export function nextTick(): Promise<void> {
b69ab31	30	return new Promise(res => setTimeout(res, 0));
b69ab31	31	}
b69ab31	32
b69ab31	33	export async function gc() {
b69ab31	34	// 'node --expose-gc' defines 'global.gc'.
b69ab31	35	// To run with yarn: yarn node --expose-gc ./node_modules/.bin/jest ...
b69ab31	36	const globalGc = global.gc;
b69ab31	37	if (globalGc != null) {
b69ab31	38	await new Promise<void>(r =>
b69ab31	39	setTimeout(() => {
b69ab31	40	globalGc();
b69ab31	41	r();
b69ab31	42	}, 0),
b69ab31	43	);
b69ab31	44	} else {
b69ab31	45	// measureMemory with 'eager' has a side effect of running the GC.
b69ab31	46	// This exists since node 14.
b69ab31	47	// 'as' used since `MeasureMemoryOptions` is outdated (node 13?).
b69ab31	48	await measureMemory({execution: 'eager'} as MeasureMemoryOptions);
b69ab31	49	}
b69ab31	50	}