In this article, we will discuss testcontainers library and how to use it to simplify our life when it comes to integration testing our code.

For the purpose of this example, I am going to use a simple application with its business centered around reviews for some courses. Basically, the app is a service that exposes some GraphQL endpoints for review creation, querying, and deletion from a PostgreSQL database via Spring Data R2DBC. The app is written in Kotlin using Spring Boot 2.7.3.