Facundo Olano
8 years ago
4 changed files with 202 additions and 6 deletions
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'use strict'; |
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const assert = require('assert'); |
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// FIXME mock redis
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const redis = require('redis').createClient(6379, 'redis-host'); |
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const LRU = require('../index'); |
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beforeEach((done) => redis.flushdb(() => done())); |
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const dbsize = () => new Promise((resolve, reject) => |
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redis.dbsize((err, result) => { |
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if (err) return reject(err); |
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resolve(result); |
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})); |
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// const printrange = (ns) => new Promise((resolve) =>
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// redis.zrange(`${ns || 'LRU-CACHE!'}-i`, 0, -1, (err, res) => { console.log(res); resolve(); }));
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// sometimes need to force a ms change so multiple lru.get have different timestamp scores
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const tick = () => new Promise((resolve) => setTimeout(resolve, 1)); |
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describe('build cache', () => { |
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it('should fail if no client given', () => |
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assert.throws(() => LRU(), /redis client is required\./)); |
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it('should fail if no max arg given', () => { |
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assert.throws(() => LRU(redis), /max number of items in cache must be specified\./); |
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assert.throws(() => LRU(redis, {}), /max number of items in cache must be specified\./); |
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}); |
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}); |
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describe('set and get methods', () => { |
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it('should save an item in the cache and allow to get it back', () => { |
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const lru = LRU(redis, 3); |
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return lru.set('key', 'hello') |
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.then(() => lru.set('key2', {message: 'goodbye'})) |
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.then(() => Promise.all([lru.get('key'), lru.get('key2')])) |
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.then((results) => { |
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assert.equal(results[0], 'hello'); |
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assert.deepEqual(results[1], {message: 'goodbye'}); |
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}); |
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}); |
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it('should return null if a key is not found in the cache', () => { |
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const lru = LRU(redis, 3); |
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return lru.get('key1') |
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.then((result) => assert.equal(result, null)); |
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}); |
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it('should save up to opts.max items in the cache', () => { |
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const lru = LRU(redis, 3); |
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return Promise.all([ |
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lru.set('k1', 'v1'), lru.set('k2', 'v2'), lru.set('k3', 'v3') |
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]) |
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.then(() => lru.get('k1')) |
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.then((r) => assert.equal(r, 'v1')) |
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.then(tick) |
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.then(() => lru.get('k2')) |
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.then((r) => assert.equal(r, 'v2')) |
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.then(tick) |
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.then(() => lru.get('k3')) |
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.then((r) => assert.equal(r, 'v3')) |
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.then(dbsize) |
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.then((r) => assert.equal(r, 4)) // DB size is #items + 1 for the index
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.then(() => lru.set('k4', 'v4')) |
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.then(() => lru.get('k1')) |
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.then((r) => assert.equal(r, null, 'k1 should have been evicted from the cache')) |
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.then(() => lru.get('k2')) |
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.then((r) => assert.equal(r, 'v2')) |
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.then(() => lru.get('k3')) // set k4, get k1, k2 => k3 out of the cache
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.then((r) => assert.equal(r, 'v3')) |
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.then(() => lru.get('k4')) |
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.then((r) => assert.equal(r, 'v4')) |
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.then(dbsize) |
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.then((r) => assert.equal(r, 4, 'db size should not have grown')); |
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}); |
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it('should keep different items in different namespaces', () => { |
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const lru1 = LRU(redis, {max: 3, namespace: 'first'}); |
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const lru2 = LRU(redis, {max: 3, namespace: 'second'}); |
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return lru1.set('k1', 'first cache') |
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.then(() => lru2.set('k1', 'second cache')) |
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.then(() => Promise.all([lru1.get('k1'), lru2.get('k1')])) |
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.then((results) => { |
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assert.equal(results[0], 'first cache'); |
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assert.equal(results[1], 'second cache'); |
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}); |
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}); |
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it('should keep the last accessed items first', () => { |
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const lru = LRU(redis, 3); |
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return lru.set('k1', 'v1') |
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.then(() => lru.set('k2', 'v2')) |
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.then(() => lru.set('k3', 'v3')) |
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.then(() => lru.get('k2')) // k2 last
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.then(tick) |
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.then(() => lru.get('k3')) // k3 second
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.then(tick) |
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.then(() => lru.get('k1')) // k1 first
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.then(tick) |
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.then(() => lru.set('k4', 'v4')) // should evict oldest => k2 out
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.then(() => lru.get('k2')) |
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.then((result) => { |
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assert.equal(result, null); |
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}); |
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}); |
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it('should update value and last accessed score when setting a key again', () => { |
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const lru = LRU(redis, 3); |
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return lru.set('k1', 'v1') |
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.then(() => lru.set('k2', 'v2')) |
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.then(() => lru.set('k3', 'v3')) |
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.then(() => lru.get('k2')) |
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.then(() => lru.get('k3')) |
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.then(() => lru.get('k1')) |
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.then(() => lru.set('k2', 'v2')) // k2 back to front, k3 is oldest
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.then(() => lru.set('k4', 'v4')) // k3 out
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.then(() => lru.get('k3')) |
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.then((result) => { |
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assert.equal(result, null); |
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}); |
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}); |
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it('should not update last accessed score on a different namespace', () => { |
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const lru1 = LRU(redis, {max: 2, namespace: 'c1'}); |
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const lru2 = LRU(redis, {max: 2, namespace: 'c2'}); |
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return lru1.set('k1', 'v1') |
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.then(() => lru1.set('k2', 'v2')) |
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.then(() => lru2.set('k1', 'v1')) |
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.then(tick) |
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.then(() => lru2.set('k2', 'v2')) |
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.then(tick) |
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.then(() => lru1.get('k1')) // bumps k1 in first cache
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.then(tick) |
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.then(() => lru2.set('k3', 'v3')) // should evict k1 in second cache
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.then(() => lru2.get('k1')) |
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.then((result) => { |
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assert.equal(result, null); |
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}); |
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}); |
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}); |
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describe('peek method', () => { |
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it('should return the value without changing the recent-ness score'); |
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}); |
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describe('del method', () => { |
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it('should remove the key from the cache and preserve the rest'); |
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it('should not remove from other namespaces'); |
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}); |
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describe('reset method', () => { |
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it('should remove all keys from the cache'); |
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it('should not empty other namespaces'); |
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}); |
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describe('has method', () => { |
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it('should return true if the item is in the cache without affecting the recent-ness'); |
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it('should return false if the item is not in the cache'); |
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}); |
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describe('keys method', () => { |
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it('should return all keys inside the cache'); |
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it('should not return more keys if size exceeded before'); |
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}); |
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describe('values method', () => { |
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it('should return all values inside the cache'); |
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it('should not return more values if size exceeded before'); |
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}); |
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describe('count method', () => { |
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it('should return zero if no items in the cache'); |
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it('should return the amount of items in the cache'); |
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it('should return the max size if cache size exceeded before'); |
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}); |
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