Feat/setup vitest testing, update ESLint and synchronise with main

README.md

@@ -1,10 +1,13 @@
 # 🔑 KeyCV
 
-This repository houses the backend service for the KeyCV application, designed to automate and improve parts of the job application process. The frontend (if in a separate repository) would consume this backend's APIs.
+This repository houses the backend service for the KeyCV application,
+designed to automate and improve parts of the job application process.
+The frontend (if in a separate repository) would consume this backend's APIs.
 
 ## Backend Service Overview
 
-The backend service is built with Node.js, Express, and TypeScript. Its primary responsibilities include processing job application data and providing API endpoints for the frontend.
+The backend service is built with Node.js, Express, and TypeScript. Its primary responsibilities
+include processing job application data and providing API endpoints for the frontend.
 
 ## Tech Stack (Backend)
 
@@ -44,7 +47,8 @@ npm install
 
 ### 4. Environment Variables
 
-Environment variables are crucial for configuring our application. We use a `.env.example` file as a template to define all necessary variables.
+Environment variables are crucial for configuring our application.
+We use a `.env.example` file as a template to define all necessary variables.
 
 For local development, create a `.env.local` file in the `backend/` directory:
 
@@ -55,7 +59,8 @@ cp .env.example .env.local
 Then, open `.env.local` and fill in the required environment variables specific to your local setup.
 
 > 🚨 **Warning:** </br>
-> **Ensure this file is never committed to Git, as it contains sensitive information.** (It is already ignored by `.gitignore`). On Render, add these variables via the dashboard.
+> **Ensure this file is never committed to Git, as it contains sensitive information.**
+(It is already ignored by `.gitignore`). On Render, add these variables via the dashboard.
 
 ### 5. Run the Development Server
 
@@ -65,7 +70,9 @@ To start the backend server in development mode with live reloading:
 npm run dev
 ```
 
-The `npm run dev` command uses `nodemon` to watch for changes in your source files (`src/`). It will automatically recompile your TypeScript code and restart the server, loading environment variables from `.env.local`.
+The `npm run dev` command uses `nodemon` to watch for changes in your source files (`src/`). It will
+automatically recompile your TypeScript code and restart the server, loading environment variables
+from `.env.local`.
 
 > **Note:**</br>
 > The server will typically run on `http://localhost:3000`.
@@ -92,12 +99,126 @@ npm start
 
 These scripts are run from within the `backend/` directory.
 
-- `npm run dev`: Starts the backend server in development mode with live reloading. It automatically recompiles TypeScript changes and loads environment variables from `.env.local`.
-- `npm run build`: Compiles TypeScript to JavaScript for the backend, creating production-ready files in the `dist/` directory.
+- `npm run dev`: Starts the backend server in development mode with live reloading.
+It automatically recompiles TypeScript changes and loads environment variables from `.env.local`.
+- `npm run build`: Compiles TypeScript to JavaScript for the backend, creating production-ready
+files in the `dist/` directory.
+
 - `npm start`: Starts the compiled production backend server.
-- `npm run test`: Runs tests (currently no tests configured for the backend).
+- `npm test`: Runs the complete test suite using Vitest.
+- `npm run test:watch`: Runs tests in watch mode for development.
+- `npm run test:ui`: Opens the Vitest UI for interactive testing.
+- `npm run test:coverage`: Generates test coverage reports.
+
+For contribution guidelines, including our Git branching model and commit message conventions,
+please refer to our [CONTRIBUTING.md](CONTRIBUTING.md) guide.
+
+## Testing
+
+We use **Vitest** as our testing framework, providing a fast and modern testing experience
+with TypeScript support.
+
+### Test Structure
+
+Our test suite is organized into three main categories:
+
+1. **Unit Tests** (`src/**/*.test.ts`)
+   - Service layer tests (LLM service, business logic)
+   - Utility function tests
+   - Individual component testing
+
+2. **Integration Tests** (`src/controllers/*.test.ts`)
+   - API endpoint testing
+   - Controller logic with mocked services
+   - Request/response validation
+
+3. **Basic Tests** (`src/__tests__/*.test.ts`)
+   - Smoke tests
+   - Environment validation
+   - Configuration checks
+
+### Running Tests
+
+```bash
+# Run all tests once
+npm test
+
+# Run tests in watch mode (re-runs on file changes)
+npm run test:watch
+
+# Open interactive UI for test exploration
+npm run test:ui
+
+# Generate coverage report
+npm run test:coverage
+```
+
+### Test Configuration
+
+- **Framework:** Vitest v4.0.15
+- **Environment:** Node.js
+- **Coverage Tool:** v8
+- **Mocking:** vi (Vitest's built-in mocking utilities)
+- **Globals:** Enabled (no need to import describe, it, expect)
 
-For contribution guidelines, including our Git branching model and commit message conventions, please refer to our [CONTRIBUTING.md](CONTRIBUTING.md) guide.
+### Coverage Thresholds
+
+We maintain minimum coverage thresholds:
+
+- **Lines:** 70%
+- **Functions:** 70%
+- **Branches:** 70%
+- **Statements:** 70%
+
+### Test Results
+
+![Test Results](./docs/vitest_passed.png)
+
+> All 28 tests passing across 3 test suites*
+
+### Writing Tests
+
+When adding new features, please include corresponding tests:
+
+```typescript
+import { describe, it, expect, beforeEach, vi } from "vitest";
+
+describe("FeatureName", () => {
+  beforeEach(() => {
+    // Setup code
+  });
+
+  it("should do something expected", () => {
+    // Arrange
+    const input = "test";
+
+    // Act
+    const result = yourFunction(input);
+
+    // Assert
+    expect(result).toBe("expected");
+  });
+});
+```
+
+### Mocking External Dependencies
+
+We mock external services (like the Anthropic API) to ensure fast, reliable tests:
+
+```typescript
+// Mock the Anthropic SDK
+const { mockCreate } = vi.hoisted(() => ({
+  mockCreate: vi.fn(),
+}));
+
+vi.mock("@anthropic-ai/sdk", () => ({
+  default: vi.fn(function() {
+    return {
+      messages: { create: mockCreate },
+    };
+  }),
+}));
+```
 
 ## Deployment
 
@@ -117,10 +238,12 @@ You can access the live application after Render finishes provisioning and expos
 
 ## Project Documentation
 
-All detailed project documentation has been moved to the `docs/` directory to keep the root directory clean.
+All detailed project documentation has been moved to the `docs/` directory keeping root directory clean.
 
-- **[Project Guidelines](docs/GUIDELINES.md):** High-level project goals, tech stack, and project management approach.
-- **[Deployment Guide](docs/deployment.md):** Detailed instructions for deploying the backend service on Render.
+- **[Project Guidelines](docs/GUIDELINES.md):** High-level project goals, tech stack, and project
+management approach.
+- **[Deployment Guide](docs/deployment.md):** Detailed instructions for deploying the backend service
+at Render.
 - **[Project Plan Gantt Chart](docs/gantt.html):** A visual representation of our project plan.
 - **[AI Toolkit](docs/AI_Toolkit.md):** Suggestions for leveraging AI to enhance the application's capabilities.
 

backend/eslint.config.js

@@ -12,7 +12,7 @@ export default [
       parserOptions: {
         ecmaVersion: "latest",
         sourceType: "module",
-        project: "./tsconfig.json",
+        project: "./tsconfig.eslint.json",
       },
       globals: {
         console: "readonly",

backend/src/__tests__/basic.test.ts

@@ -0,0 +1,13 @@
+/// <reference types="vitest/globals" />
+import { describe, it, expect } from "vitest";
+
+describe("Basic Test", () => {
+  it("should pass a simple test", () => {
+    expect(1 + 1).toBe(2);
+  });
+
+  it("should handle async tests", async () => {
+    const result = await Promise.resolve(42);
+    expect(result).toBe(42);
+  });
+});

backend/src/__tests__/fixtures/resumes.ts

@@ -0,0 +1,30 @@
+export const SAMPLE_RESUME_TEXT = `
+John Doe
+Software Engineer
+
+EXPERIENCE
+Senior Developer at TechCorp (2020-2024)
+- Built scalable microservices with Node.js and TypeScript
+- Led team of 5 developers
+- Improved performance by 40%
+
+SKILLS
+JavaScript, React, Node.js, PostgreSQL
+`.trim();
+
+export const SAMPLE_JOB_DESCRIPTION = `
+Senior Full-Stack Engineer
+
+Requirements:
+- 5+ years experience with TypeScript
+- React and Node.js expertise
+- PostgreSQL or similar database
+- Leadership experience preferred
+`.trim();
+
+export const createMockPdfBuffer = (): Buffer => {
+  // Minimal PDF with text
+  return Buffer.from(
+    "%PDF-1.4\n1 0 obj\n<<\n/Type /Catalog\n/Pages 2 0 R\n>>\nendobj\n2 0 obj\n<<\n/Type /Pages\n/Kids [3 0 R]\n/Count 1\n>>\nendobj\n3 0 obj\n<<\n/Type /Page\n/Parent 2 0 R\n/Contents 4 0 R\n>>\nendobj\n4 0 obj\n<<\n/Length 44\n>>\nstream\nBT\n/F1 12 Tf\n100 700 Td\n(Test Resume) Tj\nET\nendstream\nendobj\nxref\n0 5\n0000000000 65535 f\n0000000009 00000 n\n0000000058 00000 n\n0000000115 00000 n\n0000000214 00000 n\ntrailer\n<<\n/Size 5\n/Root 1 0 R\n>>\nstartxref\n338\n%%EOF",
+  );
+};

backend/src/__tests__/mocks/anthropic.mock.ts

@@ -0,0 +1,24 @@
+import { vi } from "vitest";
+import type Anthropic from "@anthropic-ai/sdk";
+
+export const createMockAnthropicResponse = (jsonContent: unknown) => ({
+  content: [
+    {
+      type: "text" as const,
+      text: JSON.stringify(jsonContent),
+    },
+  ],
+});
+
+export const createMockAnthropicClient = () => {
+  const mockCreate = vi.fn();
+
+  return {
+    client: {
+      messages: {
+        create: mockCreate,
+      },
+    } as unknown as Anthropic,
+    mockCreate,
+  };
+};

backend/src/__tests__/mocks/express.mock.ts

@@ -0,0 +1,30 @@
+import { vi } from "vitest";
+import type { Request, Response } from "express";
+
+export const createMockRequest = (
+  overrides: Partial<Request> = {},
+): Partial<Request> => ({
+  body: {},
+  params: {},
+  query: {},
+  headers: {},
+  ...overrides,
+});
+
+export const createMockResponse = (): {
+  res: Partial<Response>;
+  statusMock: ReturnType<typeof vi.fn>;
+  jsonMock: ReturnType<typeof vi.fn>;
+} => {
+  const jsonMock = vi.fn();
+  const statusMock = vi.fn().mockReturnValue({ json: jsonMock });
+
+  const res: Partial<Response> = {
+    status: statusMock,
+    json: jsonMock,
+    send: vi.fn(),
+    sendStatus: vi.fn(),
+  };
+
+  return { res, statusMock, jsonMock };
+};

backend/src/__tests__/setup.ts

@@ -0,0 +1,18 @@
+import { beforeAll, afterAll, afterEach, vi } from "vitest";
+
+// Set test environment variables
+beforeAll(() => {
+  process.env.NODE_ENV = "test";
+  process.env.ANTHROPIC_API_KEY = "test-api-key-" + Math.random();
+});
+
+// Clean up after each test
+afterEach(() => {
+  vi.clearAllMocks();
+  vi.restoreAllMocks();
+});
+
+// Final cleanup
+afterAll(() => {
+  delete process.env.ANTHROPIC_API_KEY;
+});