MCP Time Server Node

import { SlidingWindowRateLimiter } from '../../src/utils/rateLimit'; describe('SlidingWindowRateLimiter', () => { let rateLimiter: SlidingWindowRateLimiter; beforeEach(() => { jest.useFakeTimers(); }); afterEach(() => { jest.useRealTimers(); }); describe('constructor', () => { it('should create rate limiter with default values', () => { rateLimiter = new SlidingWindowRateLimiter(); expect(rateLimiter).toBeDefined(); // Default: 100 requests per 60000ms (1 minute) }); it('should create rate limiter with custom values', () => { rateLimiter = new SlidingWindowRateLimiter(50, 30000); expect(rateLimiter).toBeDefined(); // Custom: 50 requests per 30000ms (30 seconds) }); it('should read from environment variables', () => { process.env.RATE_LIMIT = '200'; process.env.RATE_LIMIT_WINDOW = '120000'; rateLimiter = new SlidingWindowRateLimiter(); // Verify the rate limiter read the environment variables const info = rateLimiter.getInfo(); expect(info.limit).toBe(200); expect(info.window).toBe(120000); // Should be able to make 200 requests for (let i = 0; i < 200; i++) { expect(rateLimiter.checkLimit()).toBe(true); } // 201st request should be blocked expect(rateLimiter.checkLimit()).toBe(false); delete process.env.RATE_LIMIT; delete process.env.RATE_LIMIT_WINDOW; }); }); describe('checkLimit', () => { beforeEach(() => { rateLimiter = new SlidingWindowRateLimiter(5, 10000); // 5 requests per 10 seconds jest.setSystemTime(new Date('2025-01-01T00:00:00Z')); }); it('should allow requests under the limit', () => { expect(rateLimiter.checkLimit()).toBe(true); expect(rateLimiter.checkLimit()).toBe(true); expect(rateLimiter.checkLimit()).toBe(true); expect(rateLimiter.checkLimit()).toBe(true); expect(rateLimiter.checkLimit()).toBe(true); }); it('should deny requests over the limit', () => { // Use up all 5 requests for (let i = 0; i < 5; i++) { expect(rateLimiter.checkLimit()).toBe(true); } // 6th request should be denied expect(rateLimiter.checkLimit()).toBe(false); }); it('should allow requests after window expires', () => { // Use up all 5 requests for (let i = 0; i < 5; i++) { rateLimiter.checkLimit(); } // Should be denied expect(rateLimiter.checkLimit()).toBe(false); // Move time forward 11 seconds (past the 10 second window) jest.advanceTimersByTime(11000); // Should be allowed again expect(rateLimiter.checkLimit()).toBe(true); }); it('should use sliding window algorithm', () => { // Make 3 requests rateLimiter.checkLimit(); rateLimiter.checkLimit(); rateLimiter.checkLimit(); // Move forward 5 seconds jest.advanceTimersByTime(5000); // Make 2 more requests (total 5) rateLimiter.checkLimit(); rateLimiter.checkLimit(); // Should be denied (at limit) expect(rateLimiter.checkLimit()).toBe(false); // Move forward 6 seconds (11 seconds total from start) jest.advanceTimersByTime(6000); // First 3 requests are now outside window // Should allow 3 more requests expect(rateLimiter.checkLimit()).toBe(true); expect(rateLimiter.checkLimit()).toBe(true); expect(rateLimiter.checkLimit()).toBe(true); // But not a 4th (since we still have 2 in the window) expect(rateLimiter.checkLimit()).toBe(false); }); }); describe('getCurrentUsage', () => { beforeEach(() => { rateLimiter = new SlidingWindowRateLimiter(10, 60000); jest.setSystemTime(new Date('2025-01-01T00:00:00Z')); }); it('should return current usage count', () => { expect(rateLimiter.getCurrentUsage()).toBe(0); rateLimiter.checkLimit(); expect(rateLimiter.getCurrentUsage()).toBe(1); rateLimiter.checkLimit(); rateLimiter.checkLimit(); expect(rateLimiter.getCurrentUsage()).toBe(3); }); it('should exclude expired requests from count', () => { rateLimiter.checkLimit(); rateLimiter.checkLimit(); expect(rateLimiter.getCurrentUsage()).toBe(2); // Move forward past window jest.advanceTimersByTime(61000); expect(rateLimiter.getCurrentUsage()).toBe(0); }); }); describe('getRetryAfter', () => { beforeEach(() => { rateLimiter = new SlidingWindowRateLimiter(3, 10000); // 3 per 10 seconds jest.setSystemTime(new Date('2025-01-01T00:00:00Z')); }); it('should return 0 when under limit', () => { rateLimiter.checkLimit(); expect(rateLimiter.getRetryAfter()).toBe(0); }); it('should return time until oldest request expires', () => { // Use up all requests rateLimiter.checkLimit(); // at 0ms jest.advanceTimersByTime(2000); rateLimiter.checkLimit(); // at 2000ms jest.advanceTimersByTime(1000); rateLimiter.checkLimit(); // at 3000ms // Now at limit expect(rateLimiter.checkLimit()).toBe(false); // Oldest request at 0ms, current time 3000ms // Expires at 10000ms, so 7000ms to wait expect(rateLimiter.getRetryAfter()).toBe(7); }); it('should handle edge case of no requests', () => { expect(rateLimiter.getRetryAfter()).toBe(0); }); }); describe('reset', () => { beforeEach(() => { rateLimiter = new SlidingWindowRateLimiter(5, 10000); }); it('should clear all request history', () => { rateLimiter.checkLimit(); rateLimiter.checkLimit(); rateLimiter.checkLimit(); expect(rateLimiter.getCurrentUsage()).toBe(3); rateLimiter.reset(); expect(rateLimiter.getCurrentUsage()).toBe(0); expect(rateLimiter.checkLimit()).toBe(true); }); }); describe('memory management', () => { it('should clean up old timestamps automatically', () => { rateLimiter = new SlidingWindowRateLimiter(1000, 60000); jest.setSystemTime(new Date('2025-01-01T00:00:00Z')); // Make 100 requests for (let i = 0; i < 100; i++) { rateLimiter.checkLimit(); } expect(rateLimiter.getCurrentUsage()).toBe(100); // Move forward past window jest.advanceTimersByTime(61000); // Make one more request to trigger cleanup rateLimiter.checkLimit(); // Should only have 1 request in memory expect(rateLimiter.getCurrentUsage()).toBe(1); }); }); describe('getInfo', () => { beforeEach(() => { rateLimiter = new SlidingWindowRateLimiter(10, 60000); jest.setSystemTime(new Date('2025-01-01T00:00:00Z')); }); it('should return rate limiter information', () => { rateLimiter.checkLimit(); rateLimiter.checkLimit(); rateLimiter.checkLimit(); const info = rateLimiter.getInfo(); expect(info).toEqual({ limit: 10, window: 60000, current: 3, remaining: 7, retryAfter: 0, }); }); it('should show retry after when at limit', () => { // Use up all 10 requests for (let i = 0; i < 10; i++) { rateLimiter.checkLimit(); } const info = rateLimiter.getInfo(); expect(info).toEqual({ limit: 10, window: 60000, current: 10, remaining: 0, retryAfter: 60, }); }); }); });