import { describe, it, expect, beforeEach, vi } from 'vitest';
import { RateLimiter, createRateLimiter, RateLimiterRegistry } from '../rate-limiter.js';
describe('RateLimiter', () => {
describe('tryAcquire', () => {
it('should acquire tokens when available', () => {
const limiter = new RateLimiter({ maxTokens: 10, refillRate: 10 });
expect(limiter.tryAcquire()).toBe(true);
expect(limiter.getRemainingTokens()).toBe(9);
});
it('should fail to acquire when no tokens available', () => {
const limiter = new RateLimiter({ maxTokens: 1, refillRate: 1, initialTokens: 0 });
expect(limiter.tryAcquire()).toBe(false);
});
it('should acquire multiple tokens at once', () => {
const limiter = new RateLimiter({ maxTokens: 10, refillRate: 10 });
expect(limiter.tryAcquire(5)).toBe(true);
expect(limiter.getRemainingTokens()).toBe(5);
});
it('should fail when not enough tokens for multi-token acquire', () => {
const limiter = new RateLimiter({ maxTokens: 3, refillRate: 1, initialTokens: 2 });
expect(limiter.tryAcquire(5)).toBe(false);
expect(limiter.getRemainingTokens()).toBe(2);
});
});
describe('acquire', () => {
it('should resolve immediately when tokens available', async () => {
const limiter = new RateLimiter({ maxTokens: 10, refillRate: 10 });
await limiter.acquire();
expect(limiter.getRemainingTokens()).toBe(9);
});
it('should wait for token refill', async () => {
const limiter = new RateLimiter({ maxTokens: 1, refillRate: 100, initialTokens: 0 });
const startTime = Date.now();
await limiter.acquire(1, 5000);
const elapsed = Date.now() - startTime;
expect(elapsed).toBeGreaterThan(5);
expect(elapsed).toBeLessThan(100);
});
it('should throw on timeout', async () => {
const limiter = new RateLimiter({ maxTokens: 1, refillRate: 0.1, initialTokens: 0 });
await expect(limiter.acquire(1, 50)).rejects.toThrow('timeout');
});
});
describe('refill', () => {
it('should refill tokens over time', async () => {
const limiter = new RateLimiter({ maxTokens: 10, refillRate: 100, initialTokens: 0 });
// Wait 50ms - should add ~5 tokens at 100 tokens/second
await new Promise(resolve => setTimeout(resolve, 50));
const tokens = limiter.getRemainingTokens();
expect(tokens).toBeGreaterThanOrEqual(3);
expect(tokens).toBeLessThanOrEqual(7);
});
it('should not exceed max tokens', async () => {
const limiter = new RateLimiter({ maxTokens: 5, refillRate: 100 });
await new Promise(resolve => setTimeout(resolve, 100));
expect(limiter.getRemainingTokens()).toBe(5);
});
});
describe('getTimeUntilAvailable', () => {
it('should return 0 when tokens available', () => {
const limiter = new RateLimiter({ maxTokens: 10, refillRate: 10 });
expect(limiter.getTimeUntilAvailable()).toBe(0);
});
it('should return estimated wait time when no tokens', () => {
const limiter = new RateLimiter({ maxTokens: 10, refillRate: 10, initialTokens: 0 });
const waitTime = limiter.getTimeUntilAvailable();
expect(waitTime).toBeGreaterThan(0);
expect(waitTime).toBeLessThanOrEqual(100);
});
});
describe('reset', () => {
it('should restore to initial state', () => {
const limiter = new RateLimiter({ maxTokens: 10, refillRate: 10 });
limiter.tryAcquire(5);
limiter.reset();
expect(limiter.getRemainingTokens()).toBe(10);
});
});
});
describe('createRateLimiter', () => {
it('should create limiter with given RPS', () => {
const limiter = createRateLimiter(5);
expect(limiter.getRemainingTokens()).toBe(5);
});
it('should allow custom burst size', () => {
const limiter = createRateLimiter(5, 10);
expect(limiter.getRemainingTokens()).toBe(10);
});
});
describe('RateLimiterRegistry', () => {
let registry: RateLimiterRegistry;
beforeEach(() => {
registry = new RateLimiterRegistry({ maxTokens: 10, refillRate: 10 });
});
it('should create new limiters on first access', () => {
const limiter = registry.get('api1');
expect(limiter).toBeInstanceOf(RateLimiter);
expect(limiter.getRemainingTokens()).toBe(10);
});
it('should return same limiter for same key', () => {
const limiter1 = registry.get('api1');
limiter1.tryAcquire(3);
const limiter2 = registry.get('api1');
expect(limiter2.getRemainingTokens()).toBe(7);
});
it('should use custom options when provided', () => {
const limiter = registry.get('api1', { maxTokens: 5, refillRate: 5 });
expect(limiter.getRemainingTokens()).toBe(5);
});
it('should remove limiters', () => {
registry.get('api1');
expect(registry.remove('api1')).toBe(true);
expect(registry.remove('api1')).toBe(false);
});
it('should clear all limiters', () => {
registry.get('api1');
registry.get('api2');
registry.clear();
// New limiter should be created with full tokens
const limiter = registry.get('api1');
expect(limiter.getRemainingTokens()).toBe(10);
});
});
