Backend certification exam readiness

Initialize a Node.js project with `npm init -y` and install Express.

Install and configure `dotenv` to load environment variables from a `.env` file.

Create a `.gitignore` file to exclude `node_modules/`, `.env`, and other sensitive or generated files.

Create an Express app, configure `express.json()` middleware, and start the server using `process.env.PORT`.

Install Mongoose and connect to a MongoDB database using `process.env.MONGO_URI`.

Define a Mongoose schema with required fields and correct data types (String, Number, Boolean, Date).

Create and export a Mongoose model from the defined schema.

Create an Express Router and mount it on a base path in the main application file.

Implement a GET route using `Model.find()` to return all resources with a 200 status code.

Implement a GET route using `Model.findById()` to return a single resource or a 404 status if not found.

Implement a POST route using `Model.create()` to save a new resource and return it with a 201 status code.

Implement a PUT route using `Model.findByIdAndUpdate(id, data, { new: true })` and return a 404 status if not found.

Implement a DELETE route using `Model.findByIdAndDelete()` and return a 204 status or a 404 status if not found.

Implement validation for required fields before creation and return a 400 status with a descriptive error message.

Detect and handle invalid ObjectId format errors in request parameters, returning a 400 status.

Implement a 404 handler middleware to catch requests for undefined routes.

Implement a global error-handling middleware with an `(err, req, res, next)` signature.

Wrap async route handlers to catch rejected promises and forward errors using `next(err)`.

Use the global error handler to return clean JSON error responses, preventing stack trace leakage in production.

Install and configure `swagger-jsdoc` and `swagger-ui-express`.

Define the base OpenAPI specification with `info` and `servers` properties in JSDoc.

Serve interactive Swagger documentation at the `/api-docs` endpoint.

Define a reusable schema component for the primary resource model, including required fields and example values.

Write a YAML JSDoc comment to document the GET-all endpoint with 200 and 500 responses.

Write a YAML JSDoc comment to document the GET-by-ID endpoint with 200, 404, and 400 responses.

Write YAML JSDoc comments to document the POST and PUT endpoints, including `requestBody` definitions that reference the reusable schema.

Write a YAML JSDoc comment to document the DELETE endpoint with 204, 404, and 500 responses.

Install and configure Jest and Supertest for testing an Express application.

Set up the test environment to automatically close the server after tests complete.

Mock the Mongoose model module using `jest.mock()` to ensure tests run without a database connection.

Replace specific Mongoose model methods (e.g., `find`, `findById`, `create`) with `jest.fn()` to control their behavior in tests.

Write integration tests for GET endpoints, asserting correct status codes, response body content, and 404 error cases.

Write integration tests for the POST endpoint, covering both successful creation (201) and validation failure (400).

Write integration tests for the PUT endpoint, covering successful updates (200) and not-found errors (404).

Write integration tests for the DELETE endpoint, covering successful deletion (204) and not-found errors (404).

Implement a POST route that uses Multer middleware to accept a file upload.

Add validation to the route to ensure a file is present in the request, returning a 400 status if missing.

Write a Supertest integration test for the file upload endpoint using `.attach()` to simulate a file upload.

Add requests for all CRUD operations, utilizing path variables and request bodies as needed.

Define and use a Postman environment variable `{{baseUrl}}` to avoid hardcoded URLs in requests.

Export the completed Postman collection as a JSON file for submission.

Push the complete project to a new GitHub repository.

Create a new web service on a hosting platform (e.g., Render, Railway) and link it to the GitHub repository.

Trigger a deployment and inspect server logs to debug and resolve any startup errors.

Verify the live API is operational and the Swagger documentation is accessible at the deployed URL.

Refactor the project to eliminate any hardcoded secrets or configuration values.

Perform a final check to confirm all API endpoints return appropriate HTTP status codes for success and error cases.

Assemble and verify all required submission artifacts: live API link, Swagger documentation link, GitHub repository link, and the exported Postman collection file.