141 lines
3.8 KiB
JavaScript
141 lines
3.8 KiB
JavaScript
/**
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* Copyright (c) 2018-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @emails oncall+javascript_foundation
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* @format
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* @flow
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*/
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'use strict';
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const Cache = require('../Cache');
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describe('Cache', () => {
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function createStore(i) {
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return {
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get: jest.fn().mockImplementation(() => null),
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set: jest.fn(),
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};
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}
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afterEach(() => {
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jest.restoreAllMocks();
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});
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it('returns null when no result is found', async () => {
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const store1 = createStore();
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const store2 = createStore();
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const cache = new Cache([store1, store2]);
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// Calling a wrapped method.
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const result = await cache.get(Buffer.from('foo'));
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expect(result).toBe(null);
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expect(store1.get).toHaveBeenCalledTimes(1);
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expect(store2.get).toHaveBeenCalledTimes(1);
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});
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it('sequentially searches up until it finds a valid result', async () => {
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const store1 = createStore(1);
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const store2 = createStore(2);
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const store3 = createStore(3);
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const cache = new Cache([store1, store2, store3]);
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// Only cache 2 can return results.
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store2.get.mockImplementation(() => 'hit!');
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const result = await cache.get(Buffer.from('foo'));
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expect(result).toBe('hit!');
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expect(store1.get).toHaveBeenCalledTimes(1);
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expect(store2.get).toHaveBeenCalledTimes(1);
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expect(store3.get).not.toHaveBeenCalled();
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});
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it('skips all cache stores when a hit is produced, based on the same key', () => {
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const store1 = createStore();
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const store2 = createStore();
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const store3 = createStore();
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const cache = new Cache([store1, store2, store3]);
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const key = Buffer.from('foo');
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store2.get.mockImplementation(() => 'hit!');
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// Get and set. Set should only affect store 1, not 2 (hit) and 3 (after).
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cache.get(key);
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cache.set(key);
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expect(store1.set).toHaveBeenCalledTimes(1);
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expect(store2.set).not.toHaveBeenCalled();
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expect(store3.set).not.toHaveBeenCalled();
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});
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it('awaits for promises on stores, even if they return undefined', async () => {
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let resolve;
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const store1 = createStore();
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const store2 = createStore();
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const promise = new Promise((res, rej) => (resolve = res));
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const cache = new Cache([store1, store2]);
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store1.get.mockImplementation(() => promise);
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const get = cache.get(Buffer.from('foo'));
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// Store 1 returns a promise, so store 2 is not called until it resolves.
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expect(store1.get).toHaveBeenCalledTimes(1);
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expect(store2.get).not.toHaveBeenCalled();
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if (!resolve) {
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throw new Error('Flow needs this');
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}
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resolve(undefined);
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await Promise.all([promise, get]);
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expect(store1.get).toHaveBeenCalledTimes(1);
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expect(store2.get).toHaveBeenCalledTimes(1);
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});
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it('throws on a buggy store set', async () => {
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jest.useFakeTimers();
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const store1 = createStore();
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const store2 = createStore();
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const cache = new Cache([store1, store2]);
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let error = null;
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store1.set.mockImplementation(() => null);
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store2.set.mockImplementation(() => Promise.reject(new RangeError('foo')));
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try {
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cache.set(Buffer.from('foo'), 'arg');
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jest.runAllTimers();
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} catch (err) {
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error = err;
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}
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expect(error).toBeInstanceOf(RangeError);
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});
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it('throws on a buggy store get', async () => {
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const store1 = createStore();
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const store2 = createStore();
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const cache = new Cache([store1, store2]);
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let error = null;
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store1.get.mockImplementation(() => null);
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store2.get.mockImplementation(() => Promise.reject(new TypeError('bar')));
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try {
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await cache.get(Buffer.from('foo'));
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} catch (err) {
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error = err;
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}
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expect(error).toBeInstanceOf(TypeError);
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});
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});
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