Test Harness for Postgres Integrations

Three-container solution for testing REST services against a Postgres database.

Why would you want this?

The purpose of a system is what it does. So it's nice to know that the application is affecting the database in its intended manner. We'll use containers because it's a convenient way to define these things in code, and most production scenarios will call for containerization as in-market test runners are typically Kubernetes wrappers.

Solution

We'll run a three-container test suite with Docker compose. Postgres will run as host alias database, our API as host alias api, and the Test Runner as host alias test. We'll explicitly define a network ensuring that all three containers are members, and use environment variables and the defined aliases to manage connections between them. We're assuming a Node ecosystem, so the Test Runner will be boilerplate jest, you should extend to suit your needs.

Prerequisites

• A Docker account

Steps

Clone the repository.

Build $ docker compose build

Run $ docker compose up

This will run all three containers, in order. The test script calls the increment endpoint twice, and manually checks the data.