Many JSON REST APIs today offer a Swagger page as documentation as a way to explore the API (see also this recent post by Jorrit). This Swagger page (aka Swagger UI) is often used by testers to interact with the API to manually construct and verify the API calls that are then implemented as an automated test.

What you may not realize, is that the Swagger UI is generated from an openapi.json or openapi.yaml file hosted by the API server. To ensure "Swagger compatibility", this must follow the OpenAPI Specification.

But if a webpage that can interact with the API is generated from this document, shouldn’t it be possible to generate test cases for this API from it also?

Let’s find out!

For one of our clients we use the Quarkus framework. Quarkus is a full-stack, Kubernetes-native Java framework, designed to work with popular Java standards, frameworks and libraries. It is possible to get into details about Quarkus, but that’s not what this post is about! This blog will tell you how to set up a simple database driven application with a full end-to-end test, using Quarkus and testcontainers.

In my previous post I showed my git and vim configuration. This post will be about random small tools that I use, such as tooling for docker and kubernetes, or just some small utilities to make life a bit easier.

In my previous post I showed you my terminal and shell, with some of the configuration I like to use. This post of 'A Developers Toolbox' will be all about git and vim. I will show you the aliases I use, how you can set up git hooks, and a useful tool to view your git log. And I will share my vim configuration, with some tips and tricks on how to use it.

Personally I like to use the terminal as much as possible, and by doing so I have a few useful tools in my 'toolbox' for my day-to-day work as a developer. This blog is the first in a trilogy, covering all the tools that I use almost daily. This first part will be all about the terminal itself. Which terminal I use, which shell I use, and how I have customized its looks.

Sealed classes are an exiting new feature of Java 17, let’s find out what they are, how to use them and why they are useful.

In Spock we can also get a hold on the arguments that are passed to method call of a mock and we can write assertions to check the parameters for certain conditions.

When we create a mock in Spock and invoke a method on the mock the arguments are matched using the equals() implementation of the argument type. If they are not equal Spock will tell us by showing a message that there are too few invocations of the method call. Let’s show this with an example. First we create some classes we want to test:

We’ll continue the plan to rate movies with Markov chains.
This time we predict ratings.

As of the release of Java 17 a new LTS has been available, but what is in it for me exactly and which features can I use during projects?
Most of the blogs I read only describe 1 version upgrade and also discuss a lot of features that are/were still in preview.
I decided to summarize which features are released from java 11 to 17 (one LTS to another) and in specific only those that I thought could be interesting during my everyday work as a Java developer.
So in this blog I wont be talking about the features that are in Preview or tools that came with the new JDK’s.

We’ll continue the plan to rate movies with Markov chains.
This time we’ll learn a Markov chain from movie plots.