test(api): verify async service layer mocking for resume upload route

app/api/student/resume/upload/route.mock-integrations.test.ts

@@ -0,0 +1,133 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { POST } from './route';
+import { RateLimiter } from '@/lib/rate-limit';
+import { parseResume, hasValidFileSignature } from '@/lib/resume-parser';
+
+// 1. Mock the External Modules and Service Layers
+vi.mock('@/utils/getClientIp', () => ({
+  getClientIp: vi.fn(() => '127.0.0.1'),
+}));
+
+vi.mock('@/lib/rate-limit', () => {
+  const RateLimiterMock = vi.fn();
+  RateLimiterMock.prototype.check = vi.fn().mockResolvedValue(true);
+  return { RateLimiter: RateLimiterMock };
+});
+
+vi.mock('@/lib/resume-parser', () => ({
+  parseResume: vi.fn(),
+  hasValidFileSignature: vi.fn().mockReturnValue(true),
+  ALLOWED_MIME_TYPES: [
+    'application/pdf',
+    'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+  ],
+  MAX_FILE_SIZE: 5 * 1024 * 1024, // 5MB
+}));
+
+describe('API Route: Student Resume Upload (Mock Integrations)', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  // THE FIX: Explicitly mock formData() to bypass Vitest parsing issues
+  const createMockRequest = (
+    fileName = 'resume.pdf',
+    fileType = 'application/pdf',
+    fieldName = 'resume'
+  ) => {
+    const formData = new FormData();
+    const file = new File(['dummy pdf buffer content'], fileName, { type: fileType });
+    if (fieldName) formData.append(fieldName, file);
+
+    const req = new Request('http://localhost/api/student/resume/upload', {
+      method: 'POST',
+      // We don't attach the body here to avoid parsing crashes
+    });
+
+    // We force the request to resolve our formData object when asked
+    req.formData = vi.fn().mockResolvedValue(formData) as unknown as () => Promise<FormData>;
+
+    return req;
+  };
+
+  it('1. should test service loading paths to ensure successful parsing returns 200 (mock success)', async () => {
+    // Arrange: Mock the async service to succeed
+    const mockParsedData = { name: 'Priyanuj', skills: ['React', 'Next.js'] };
+    vi.mocked(parseResume).mockResolvedValueOnce(mockParsedData);
+
+    const req = createMockRequest();
+
+    // Act
+    const res = await POST(req);
+    const json = await res.json();
+
+    // Assert
+    expect(res.status).toBe(200);
+    expect(json.success).toBe(true);
+    expect(json.data).toEqual(mockParsedData);
+    expect(parseResume).toHaveBeenCalledTimes(1);
+  });
+
+  it('2. should assert local cache layers (RateLimiter) block requests before triggering async services', async () => {
+    // Arrange: Mock the RateLimiter cache to block the user
+    vi.mocked(RateLimiter.prototype.check).mockResolvedValueOnce(false);
+
+    const req = createMockRequest();
+
+    // Act
+    const res = await POST(req);
+    const json = await res.json();
+
+    // Assert: Blocked with 429, and parseResume is NEVER called
+    expect(res.status).toBe(429);
+    expect(json.error).toMatch(/Too many requests/i);
+    expect(parseResume).not.toHaveBeenCalled();
+  });
+
+  it('3. should verify correct fallback procedures during fake endpoint/parsing errors', async () => {
+    // Arrange: Simulate the PDF parser crashing or timing out
+    vi.mocked(parseResume).mockRejectedValueOnce(new Error('Parser timeout'));
+
+    const req = createMockRequest();
+
+    // Act
+    const res = await POST(req);
+    const json = await res.json();
+
+    // Assert: Route catches the error safely and returns 422
+    expect(res.status).toBe(422);
+    expect(json.success).toBe(false);
+    expect(json.error).toMatch(/Failed to parse resume/i);
+  });
+
+  it('4. should block invalid file signatures without hitting the parser service', async () => {
+    // Arrange: Simulate a user renaming a .exe file to .pdf
+    vi.mocked(hasValidFileSignature).mockReturnValueOnce(false);
+
+    const req = createMockRequest();
+
+    // Act
+    const res = await POST(req);
+    const json = await res.json();
+
+    // Assert: Fails security check (400) before reaching the async parser
+    expect(res.status).toBe(400);
+    expect(json.error).toMatch(/File content does not match its type/i);
+    expect(parseResume).not.toHaveBeenCalled();
+  });
+
+  it('5. should reject requests with missing formData fields without processing', async () => {
+    // Arrange: Send a request where the file is named 'wrong_field' instead of 'resume'
+    const req = createMockRequest('test.pdf', 'application/pdf', 'wrong_field_name');
+
+    // Act
+    const res = await POST(req);
+    const json = await res.json();
+
+    // Assert: Immediately fails validation (400)
+    expect(res.status).toBe(400);
+    expect(json.error).toMatch(/No resume file provided/i);
+    expect(RateLimiter.prototype.check).toHaveBeenCalled();
+    expect(parseResume).not.toHaveBeenCalled();
+  });
+});