Refactor socket.io controller

test/util/token-bucket.js

@@ -0,0 +1,58 @@
+const assert = require('assert');
+const TokenBucket = require('../../lib/util/token-bucket').TokenBucket;
+
+describe('TokenBucket', () => {
+    describe('#throttle', () => {
+        let bucket;
+        beforeEach(() => {
+            bucket = new TokenBucket(5, 5);
+        });
+
+        it('consumes capacity and then throttles', () => {
+            assert(!bucket.throttle(), 'should not be empty yet');
+            assert(!bucket.throttle(), 'should not be empty yet');
+            assert(!bucket.throttle(), 'should not be empty yet');
+            assert(!bucket.throttle(), 'should not be empty yet');
+            assert(!bucket.throttle(), 'should not be empty yet');
+            assert(bucket.throttle(), 'should be empty now');
+        });
+
+        it('refills tokens', () => {
+            bucket.count = 0;
+            const oldRefill = bucket.lastRefill = Date.now() - 1000;
+            assert(!bucket.throttle(), 'should have refilled');
+            assert(bucket.lastRefill >= oldRefill + 1000, 'should have updated lastRefill');
+        });
+
+        it('refills at most {capacity} tokens', () => {
+            bucket.count = 0;
+            bucket.lastRefill = Date.now() - 10000;
+            bucket.throttle();
+            assert.strictEqual(bucket.count, 4);
+        });
+
+        it('does a partial refill', () => {
+            bucket.count = 0;
+            bucket.lastRefill = Date.now() - 400;
+            bucket.throttle();
+            assert.strictEqual(bucket.count, 1);
+        });
+
+        it('skips refilling if delta = 0', () => {
+            bucket.count = 0;
+            const oldRefill = bucket.lastRefill;
+            bucket.throttle();
+            assert.strictEqual(bucket.count, 0);
+            assert.strictEqual(bucket.lastRefill, oldRefill);
+        });
+
+        it('handles fractional refill rates', () => {
+            bucket = new TokenBucket(5, 0.1);
+            bucket.count = 0;
+            assert(bucket.throttle());
+            bucket.lastRefill = Date.now() - 10000;
+            assert(!bucket.throttle());
+            assert.strictEqual(bucket.count, 0);
+        });
+    });
+});