🚀 Building and Testing a Dockerized Book API with Keploy

Ankita Kumari — Sat, 28 Jun 2025 13:25:48 +0000

Over the past week, I worked on an exciting project — building a RESTful Book API using Node.js, containerizing it with Docker, and automating test generation using Keploy. Here’s a complete walkthrough of what I built, learned, and achieved!

🔧 Tech Stack

Layer	Technology
Language	JavaScript (Node.js)
Framework	Express.js
Database	PostgreSQL (via Docker)
DB Client	`pg` (node-postgres)
Testing	Jest, Supertest
Automation	Keploy
Containerization	Docker & Docker Compose

✨ Features
✅ API Endpoints
👥 Users
GET /users – Get all users

POST /users – Create a user

PUT /users/:id – Update a user

DELETE /users/:id – Delete a user

📚 Books
GET /api/books – Get all books

POST /api/books – Add a book

GET /api/books/:id – Get a book by ID

DELETE /api/books/:id – Delete a book

🧪 Testing Strategy
My goal was to achieve 100% test coverage with the following layers:

✅ Unit Tests – Test individual components

✅ Integration Tests – Test DB operations

✅ API Tests – Using Supertest

✅ Auto-generated Tests – via Keploy

🐰 How Keploy Helped
I integrated Keploy CLI inside my Docker Compose setup. It captured real HTTP requests and database interactions and auto-generated test cases in the background!

📦 Setup Command
docker run -it --network="book-api-server_default" \
-v "$(pwd)":/keploy -w /keploy \
-e KEPLOY_MODE=record \
-e KEPLOY_APP_HOST=node-app:5000 \
-e KEPLOY_DB_DSN="postgres://postgres:#Anku265482@pgdb:5432/bookdb?sslmode=disable" \
ghcr.io/keploy/keploy
After hitting a few API routes with curl, Keploy generated test cases in keploy-tests/

🧠 What I Learned
Managing multi-container apps with Docker Compose

Connecting Node.js with PostgreSQL in Docker

Handling database connection errors inside Docker

Writing clean, layered API architecture

Using Keploy to record, replay, and test real API usage

Solving tricky Git submodule and push errors

📸 Screenshots
✅ Test Coverage Report

🐰 Keploy CLI Output

📂 Generated Keploy Test Files

🐳 API Curl Request

🔗 Links
GitHub Repo: https://github.com/ankita-2311/book-api-server

💬 Feedback? Let’s connect on LinkedIn

🏁 Final Words
Keploy simplified testing for me — instead of writing boilerplate test cases, I just interacted with my API and let Keploy generate them. Highly recommended for any project with REST APIs!

If you enjoyed reading or found this helpful, do share and tag @KeployIO. 💙

DEV Community: Ankita Kumari

🚀 Building and Testing a Dockerized Book API with Keploy