What Can I Do for You? - Petri Kainulainen

If you ever ask yourself some of these questions:

How can I write (or generate) meaningful tests that are easy to read and maintain?
How can I be a better developer?
How can I design an architecture that makes code easy to maintain and supports AI-assisted development?
How can I do X with Spring or Spring Boot?

You have come to the right place! I can help you to find answers to these questions. I promise that:

I will teach you new technical skills. At the moment I am mostly writing about automated testing, Spring Framework, and Spring Boot.
I will make you think. Some of my non-technical blog posts might be provocative and you might not agree with me. But I promise that every blog post should raise some thoughts. If it doesn’t, I have failed.

What Kind of Stuff Do I Write?

If this is your first visit to my website, you might want to check my tutorials. Here are my latest tutorials:

JUnit 5 Tutorial helps you to get started with JUnit 5.
Spring MockMvc Tutorial helps you to write both unit and integration tests for your Spring and Spring Boot web applications.
WireMock Tutorial describes how you can write proper tests for code that invokes external HTTP APIs.

You can also check my latest blog posts.

I am a software architect who lives in Siilinjärvi, Finland. I am passionate about the following things:

Kaizen. There is always something that will make my job easier and help me to be more productive. I like continuous improvement because it doesn’t provide me any answers. I have to find those answers myself and I love the journey.
Learning new things. The world isn’t a static place and learning new skills is an essential part of my job. It makes my work a lot more interesting and helps me to select the best tool for the job.
Automated testing. I am an automated testing fanatic. I started my career as a unit testing fanatic, but during the last few years I have learned that integration testing, API testing, and end-to-end testing are important too. Sadly, I haven’t written (or generated) a perfect test (yet), but I think that every test I write (or generate) will take me one test closer to that goal.
Software architecture. I think that architecture work is extremely important in the age of AI, and in the future, we must pay much more attention to it because systems with bad architecture deteriorate faster than well-architected systems.
Human readable code. If there is a possibility that a human reads “my code”, it must be human readable. It doesn’t have to be most beautiful code I have ever seen, but I must be able to read it without extra effort. Otherwise, I won’t read it, and I won’t force anyone else to read it either.

If you are active on social media, I would love to connect with you. You can check out my social media profiles by clicking these links: