rate-limiter.test.ts•5 kB
import { describe, it, expect, beforeEach, vi } from 'vitest';
import { TelemetryRateLimiter } from '../../../src/telemetry/rate-limiter';
describe('TelemetryRateLimiter', () => {
let rateLimiter: TelemetryRateLimiter;
beforeEach(() => {
vi.useFakeTimers();
rateLimiter = new TelemetryRateLimiter(1000, 5); // 5 events per second
vi.clearAllMocks();
});
afterEach(() => {
vi.useRealTimers();
});
describe('allow()', () => {
it('should allow events within the limit', () => {
for (let i = 0; i < 5; i++) {
expect(rateLimiter.allow()).toBe(true);
}
});
it('should block events exceeding the limit', () => {
// Fill up the limit
for (let i = 0; i < 5; i++) {
expect(rateLimiter.allow()).toBe(true);
}
// Next event should be blocked
expect(rateLimiter.allow()).toBe(false);
});
it('should allow events again after the window expires', () => {
// Fill up the limit
for (let i = 0; i < 5; i++) {
rateLimiter.allow();
}
// Should be blocked
expect(rateLimiter.allow()).toBe(false);
// Advance time to expire the window
vi.advanceTimersByTime(1100);
// Should allow events again
expect(rateLimiter.allow()).toBe(true);
});
});
describe('wouldAllow()', () => {
it('should check without modifying state', () => {
// Fill up 4 of 5 allowed
for (let i = 0; i < 4; i++) {
rateLimiter.allow();
}
// Check multiple times - should always return true
expect(rateLimiter.wouldAllow()).toBe(true);
expect(rateLimiter.wouldAllow()).toBe(true);
// Actually use the last slot
expect(rateLimiter.allow()).toBe(true);
// Now should return false
expect(rateLimiter.wouldAllow()).toBe(false);
});
});
describe('getStats()', () => {
it('should return accurate statistics', () => {
// Use 3 of 5 allowed
for (let i = 0; i < 3; i++) {
rateLimiter.allow();
}
const stats = rateLimiter.getStats();
expect(stats.currentEvents).toBe(3);
expect(stats.maxEvents).toBe(5);
expect(stats.windowMs).toBe(1000);
expect(stats.utilizationPercent).toBe(60);
expect(stats.remainingCapacity).toBe(2);
});
it('should track dropped events', () => {
// Fill up the limit
for (let i = 0; i < 5; i++) {
rateLimiter.allow();
}
// Try to add more - should be dropped
rateLimiter.allow();
rateLimiter.allow();
const stats = rateLimiter.getStats();
expect(stats.droppedEvents).toBe(2);
});
});
describe('getTimeUntilCapacity()', () => {
it('should return 0 when capacity is available', () => {
expect(rateLimiter.getTimeUntilCapacity()).toBe(0);
});
it('should return time until capacity when at limit', () => {
// Fill up the limit
for (let i = 0; i < 5; i++) {
rateLimiter.allow();
}
const timeUntilCapacity = rateLimiter.getTimeUntilCapacity();
expect(timeUntilCapacity).toBeGreaterThan(0);
expect(timeUntilCapacity).toBeLessThanOrEqual(1000);
});
});
describe('updateLimits()', () => {
it('should dynamically update rate limits', () => {
// Update to allow 10 events per 2 seconds
rateLimiter.updateLimits(2000, 10);
// Should allow 10 events
for (let i = 0; i < 10; i++) {
expect(rateLimiter.allow()).toBe(true);
}
// 11th should be blocked
expect(rateLimiter.allow()).toBe(false);
const stats = rateLimiter.getStats();
expect(stats.maxEvents).toBe(10);
expect(stats.windowMs).toBe(2000);
});
});
describe('reset()', () => {
it('should clear all state', () => {
// Use some events and drop some
for (let i = 0; i < 7; i++) {
rateLimiter.allow();
}
// Reset
rateLimiter.reset();
const stats = rateLimiter.getStats();
expect(stats.currentEvents).toBe(0);
expect(stats.droppedEvents).toBe(0);
// Should allow events again
expect(rateLimiter.allow()).toBe(true);
});
});
describe('sliding window behavior', () => {
it('should correctly implement sliding window', () => {
const timestamps: number[] = [];
// Add events at different times
for (let i = 0; i < 3; i++) {
expect(rateLimiter.allow()).toBe(true);
timestamps.push(Date.now());
vi.advanceTimersByTime(300);
}
// Should still have capacity (3 events used, 2 slots remaining)
expect(rateLimiter.allow()).toBe(true);
expect(rateLimiter.allow()).toBe(true);
// Should be at limit (5 events used)
expect(rateLimiter.allow()).toBe(false);
// Advance time for first event to expire
vi.advanceTimersByTime(200);
// Should have capacity again as first event is outside window
expect(rateLimiter.allow()).toBe(true);
});
});
});