vscode/test/smoke/src/utils.ts

/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { Suite, Context } from 'mocha';
import { Application, ApplicationOptions, Logger } from '../../automation';

export function describeRepeat(n: number, description: string, callback: (this: Suite) => void): void {
	for (let i = 0; i < n; i++) {
		describe(`${description} (iteration ${i})`, callback);
	}
}

export function itRepeat(n: number, description: string, callback: (this: Context) => any): void {
	for (let i = 0; i < n; i++) {
		it(`${description} (iteration ${i})`, callback);
	}
}

/**
 * Defines a test-case that will run but will be skips it if it throws an exception. This is useful
 * to get some runs in CI when trying to stabilize a flaky test, without failing the build. Note
 * that this only works if something inside the test throws, so a test's overall timeout won't work
 * but throwing due to a polling timeout will.
 * @param title The test-case title.
 * @param callback The test-case callback.
 */
export function itSkipOnFail(title: string, callback: (this: Context) => any): void {
	it(title, function () {
		return Promise.resolve().then(() => {
			return callback.apply(this, arguments);
		}).catch(e => {
			console.warn(`Test "${title}" failed but was marked as skip on fail:`, e);
			this.skip();
		});
	});
}

export function installAllHandlers(logger: Logger, optionsTransform?: (opts: ApplicationOptions) => ApplicationOptions) {
	installDiagnosticsHandler(logger);
	installAppBeforeHandler(optionsTransform);
	installAppAfterHandler();
}

export function installDiagnosticsHandler(logger: Logger, appFn?: () => Application | undefined) {

	// Before each suite
	before(async function () {
		const suiteTitle = this.currentTest?.parent?.title;
		logger.log('');
		logger.log(`>>> Suite start: '${suiteTitle ?? 'unknown'}' <<<`);
		logger.log('');
	});

	// Before each test
	beforeEach(async function () {
		const testTitle = this.currentTest?.title;
		logger.log('');
		logger.log(`>>> Test start: '${testTitle ?? 'unknown'}' <<<`);
		logger.log('');

		const app: Application = appFn?.() ?? this.app;
		await app?.startTracing(testTitle ?? 'unknown');
	});

	// After each test
	afterEach(async function () {
		const currentTest = this.currentTest;
		if (!currentTest) {
			return;
		}

		const failed = currentTest.state === 'failed';
		const testTitle = currentTest.title;
		logger.log('');
		if (failed) {
			logger.log(`>>> !!! FAILURE !!! Test end: '${testTitle}' !!! FAILURE !!! <<<`);
		} else {
			logger.log(`>>> Test end: '${testTitle}' <<<`);
		}
		logger.log('');

		const app: Application = appFn?.() ?? this.app;
		await app?.stopTracing(testTitle.replace(/[^a-z0-9\-]/ig, '_'), failed);
	});
}

function installAppBeforeHandler(optionsTransform?: (opts: ApplicationOptions) => ApplicationOptions) {
	before(async function () {
		this.app = createApp(this.defaultOptions, optionsTransform);
		await this.app.start();
	});
}

export function installAppAfterHandler(appFn?: () => Application | undefined, joinFn?: () => Promise<unknown>) {
	after(async function () {
		const app: Application = appFn?.() ?? this.app;
		if (app) {
			await app.stop();
		}

		if (joinFn) {
			await joinFn();
		}
	});
}

export function createApp(options: ApplicationOptions, optionsTransform?: (opts: ApplicationOptions) => ApplicationOptions): Application {
	if (optionsTransform) {
		options = optionsTransform({ ...options });
	}

	const app = new Application({
		...options,
		userDataDir: getRandomUserDataDir(options)
	});

	return app;
}

export function getRandomUserDataDir(options: ApplicationOptions): string {

	// Pick a random user data dir suffix that is not
	// too long to not run into max path length issues
	// https://github.com/microsoft/vscode/issues/34988
	const userDataPathSuffix = [...Array(8)].map(() => Math.random().toString(36)[3]).join('');

	return options.userDataDir.concat(`-${userDataPathSuffix}`);
}

export function timeout(i: number) {
	return new Promise<void>(resolve => {
		setTimeout(() => {
			resolve();
		}, i);
	});
}

export interface ITask<T> {
	(): T;
}

export async function retry<T>(task: ITask<Promise<T>>, delay: number, retries: number, onBeforeRetry?: () => Promise<unknown>): Promise<T> {
	let lastError: Error | undefined;

	for (let i = 0; i < retries; i++) {
		try {
			if (i > 0 && typeof onBeforeRetry === 'function') {
				try {
					await onBeforeRetry();
				} catch (error) {
					console.warn(`onBeforeRetry failed with: ${error}`);
				}
			}

			return await task();
		} catch (error) {
			lastError = error;

			await timeout(delay);
		}
	}

	throw lastError;
}