test(middleware): add rate limit tests

Author: Vishvadharman

middleware.test.ts

@@ -0,0 +1,88 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { NextRequest, NextResponse } from 'next/server';
+import { middleware } from './middleware';
+import { rateLimit } from '@/lib/rate-limit';
+
+vi.mock('@/lib/rate-limit', () => ({
+  rateLimit: vi.fn(),
+}));
+
+describe('middleware', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('calls NextResponse.next when rate limit succeeds', () => {
+    vi.mocked(rateLimit).mockReturnValue({
+      success: true,
+      limit: 60,
+      remaining: 59,
+      reset: 123456789,
+    });
+
+    const nextSpy = vi.spyOn(NextResponse, 'next');
+
+    const request = new NextRequest('http://localhost:3000/api/streak?user=octocat');
+    middleware(request);
+
+    expect(nextSpy).toHaveBeenCalled();
+  });
+
+  it('returns 429 when rate limit fails', () => {
+    vi.mocked(rateLimit).mockReturnValue({
+      success: false,
+      limit: 60,
+      remaining: 0,
+      reset: 123456789,
+    });
+
+    const request = new NextRequest('http://localhost:3000/api/streak?user=octocat');
+    const response = middleware(request);
+
+    expect(response.status).toBe(429);
+  });
+
+  it('returns too many requests error body when rate limit fails', async () => {
+    vi.mocked(rateLimit).mockReturnValue({
+      success: false,
+      limit: 60,
+      remaining: 0,
+      reset: 123456789,
+    });
+
+    const request = new NextRequest('http://localhost:3000/api/streak?user=octocat');
+    const response = middleware(request);
+
+    await expect(response.json()).resolves.toEqual({
+      error: 'Too many requests',
+    });
+  });
+
+  it('sets X-RateLimit-Limit header when rate limit succeeds', () => {
+    vi.mocked(rateLimit).mockReturnValue({
+      success: true,
+      limit: 60,
+      remaining: 59,
+      reset: 123456789,
+    });
+
+    const request = new NextRequest('http://localhost:3000/api/streak?user=octocat');
+    const response = middleware(request);
+
+    expect(response.headers.get('X-RateLimit-Limit')).toBe('60');
+  });
+
+  it('sets X-RateLimit-Remaining header when rate limit succeeds', () => {
+    vi.mocked(rateLimit).mockReturnValue({
+      success: true,
+      limit: 60,
+      remaining: 59,
+      reset: 123456789,
+    });
+
+    const request = new NextRequest('http://localhost:3000/api/streak?user=octocat');
+    const response = middleware(request);
+
+    expect(response.headers.get('X-RateLimit-Remaining')).toBe('59');
+  });
+});