vscode/src/vs/base/test/common/cache.test.ts

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

'use strict';

import * as assert from 'assert';
import Cache from 'vs/base/common/cache';
import { TPromise } from 'vs/base/common/winjs.base';

suite('Cache', () => {

	test('simple value', () => {
		let counter = 0;
		const cache = new Cache(() => TPromise.as(counter++));

		return cache.get()
			.then(c => assert.equal(c, 0), () => assert.fail())
			.then(() => cache.get())
			.then(c => assert.equal(c, 0), () => assert.fail());
	});

	test('simple error', () => {
		let counter = 0;
		const cache = new Cache(() => TPromise.wrapError(new Error(String(counter++))));

		return cache.get()
			.then(() => assert.fail(), err => assert.equal(err.message, 0))
			.then(() => cache.get())
			.then(() => assert.fail(), err => assert.equal(err.message, 0));
	});

	test('should retry cancellations', () => {
		let counter1 = 0, counter2 = 0;

		const cache = new Cache(() => {
			counter1++;
			return TPromise.timeout(1).then(() => counter2++);
		});

		assert.equal(counter1, 0);
		assert.equal(counter2, 0);
		let promise = cache.get();
		assert.equal(counter1, 1);
		assert.equal(counter2, 0);
		promise.cancel();
		assert.equal(counter1, 1);
		assert.equal(counter2, 0);

		promise = cache.get();
		assert.equal(counter1, 2);
		assert.equal(counter2, 0);

		return promise
			.then(c => {
				assert.equal(counter1, 2);
				assert.equal(counter2, 1);
			})
			.then(() => cache.get())
			.then(c => {
				assert.equal(counter1, 2);
				assert.equal(counter2, 1);
			});
	});
});