test(refresh-rate-limiter): add error resilience coverage

Author: chavanGaneshDatta

services/github/refresh-rate-limiter.error-resilience.test.ts

@@ -0,0 +1,81 @@
+// services/github/refresh-rate-limiter.error-resilience.test.ts
+
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { refreshRateLimiter } from './refresh-rate-limiter';
+
+describe('RefreshRateLimiter Error Resilience', () => {
+  const originalEnv = process.env.MAX_REFRESHES_PER_HOUR;
+
+  beforeEach(() => {
+    refreshRateLimiter.reset();
+    delete process.env.MAX_REFRESHES_PER_HOUR;
+  });
+
+  afterEach(() => {
+    refreshRateLimiter.reset();
+
+    if (originalEnv) {
+      process.env.MAX_REFRESHES_PER_HOUR = originalEnv;
+    } else {
+      delete process.env.MAX_REFRESHES_PER_HOUR;
+    }
+  });
+
+  it('falls back to default limit when environment value is invalid', () => {
+    process.env.MAX_REFRESHES_PER_HOUR = 'invalid';
+
+    const result = refreshRateLimiter.checkLimit('127.0.0.1');
+
+    expect(result.success).toBe(true);
+    expect(result.limit).toBe(3);
+    expect(result.remaining).toBe(2);
+  });
+
+  it('falls back to default limit when environment value is zero', () => {
+    process.env.MAX_REFRESHES_PER_HOUR = '0';
+
+    const result = refreshRateLimiter.checkLimit('127.0.0.1');
+
+    expect(result.success).toBe(true);
+    expect(result.limit).toBe(3);
+  });
+
+  it('handles malformed or whitespace-only client identifiers safely', () => {
+    const result = refreshRateLimiter.checkLimit('   ');
+
+    expect(result.success).toBe(true);
+    expect(result.limit).toBe(3);
+    expect(result.remaining).toBe(2);
+  });
+
+  it('recovers correctly after reset is called', () => {
+    refreshRateLimiter.setLimit(1);
+
+    expect(refreshRateLimiter.checkLimit('192.168.1.1').success).toBe(true);
+
+    expect(refreshRateLimiter.checkLimit('192.168.1.1').success).toBe(false);
+
+    refreshRateLimiter.reset();
+
+    const result = refreshRateLimiter.checkLimit('192.168.1.1');
+
+    expect(result.success).toBe(true);
+    expect(result.limit).toBe(3);
+    expect(result.remaining).toBe(2);
+  });
+
+  it('maintains stable behavior across repeated checks after limit exhaustion', () => {
+    refreshRateLimiter.setLimit(1);
+
+    expect(refreshRateLimiter.checkLimit('10.0.0.1').success).toBe(true);
+
+    const blocked1 = refreshRateLimiter.checkLimit('10.0.0.1');
+    const blocked2 = refreshRateLimiter.checkLimit('10.0.0.1');
+
+    expect(blocked1.success).toBe(false);
+    expect(blocked2.success).toBe(false);
+
+    expect(blocked1.remaining).toBe(0);
+    expect(blocked2.remaining).toBe(0);
+  });
+});