test(github): verify rate limiter edge cases and missing parameter fallbacks

Author: ashishraj1504

services/github/refresh-rate-limiter.empty-fallback.test.ts

@@ -0,0 +1,94 @@
+// @vitest-environment node
+
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { refreshRateLimiter } from './refresh-rate-limiter';
+
+const FIXED_NOW = new Date('2026-06-02T00:00:00.000Z').valueOf();
+
+describe('RefreshRateLimiter Empty Fallback Verification', () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+    vi.setSystemTime(FIXED_NOW);
+    vi.stubEnv('MAX_REFRESHES_PER_HOUR', 'not-a-number');
+    refreshRateLimiter.reset();
+  });
+
+  afterEach(() => {
+    refreshRateLimiter.reset();
+    vi.clearAllTimers();
+    vi.useRealTimers();
+    vi.unstubAllEnvs();
+    vi.restoreAllMocks();
+  });
+
+  it('throws for empty object and empty array runtime payloads', () => {
+    expect(() => Reflect.apply(refreshRateLimiter.checkLimit, refreshRateLimiter, [{}])).toThrow(
+      TypeError
+    );
+    expect(() => Reflect.apply(refreshRateLimiter.checkLimit, refreshRateLimiter, [[]])).toThrow(
+      TypeError
+    );
+  });
+
+  it('throws for null and numeric runtime payloads', () => {
+    expect(() => Reflect.apply(refreshRateLimiter.checkLimit, refreshRateLimiter, [null])).toThrow(
+      TypeError
+    );
+    expect(() => Reflect.apply(refreshRateLimiter.checkLimit, refreshRateLimiter, [0])).toThrow(
+      TypeError
+    );
+  });
+
+  it('accepts whitespace strings and still returns the default limiter structure', () => {
+    const result = refreshRateLimiter.checkLimit('   ');
+
+    expect(result.success).toBe(true);
+    expect(result.limit).toBe(3);
+    expect(result.remaining).toBe(2);
+    expect(result.reset).toBe(FIXED_NOW + 60 * 60 * 1000);
+  });
+
+  it('honors a stubbed hourly limit for repeated checks', () => {
+    vi.stubEnv('MAX_REFRESHES_PER_HOUR', '2');
+    refreshRateLimiter.reset();
+
+    const first = refreshRateLimiter.checkLimit('203.0.113.5');
+    const second = refreshRateLimiter.checkLimit('203.0.113.5');
+    const third = refreshRateLimiter.checkLimit('203.0.113.5');
+
+    expect(first.success).toBe(true);
+    expect(first.limit).toBe(2);
+    expect(first.remaining).toBe(1);
+
+    expect(second.success).toBe(true);
+    expect(second.limit).toBe(2);
+    expect(second.remaining).toBe(0);
+
+    expect(third.success).toBe(false);
+    expect(third.limit).toBe(2);
+    expect(third.remaining).toBe(0);
+  });
+
+  it('resets back to production defaults after a custom limit has been applied', () => {
+    refreshRateLimiter.setLimit(1);
+
+    const allowed = refreshRateLimiter.checkLimit('198.51.100.1');
+    const blocked = refreshRateLimiter.checkLimit('198.51.100.1');
+
+    expect(allowed.success).toBe(true);
+    expect(allowed.limit).toBe(1);
+    expect(allowed.remaining).toBe(0);
+
+    expect(blocked.success).toBe(false);
+    expect(blocked.limit).toBe(1);
+    expect(blocked.remaining).toBe(0);
+
+    refreshRateLimiter.reset();
+
+    const resetResult = refreshRateLimiter.checkLimit('198.51.100.1');
+
+    expect(resetResult.success).toBe(true);
+    expect(resetResult.limit).toBe(3);
+    expect(resetResult.remaining).toBe(2);
+  });
+});