144. WrocławJUG

As SoftwareMill turns 10, let’s celebrate!

We’re happy to join Wrocław JUG on the 8th of October, 2019 with the following presentations:

1. Property-based testing - let your testing library work for you

Don’t ask what you can do for your testing library, ask what it can do for you! So what can it do? It turns out that much more than displaying a nice green and red report. What if we make the library generate the test data? And while we’re at it, maybe it could also think of the edge cases for which our code is wrong? Oh, and when it finds them, it should simplify them a bit before returning to us, so that we can quickly identify the root cause of the problem. And repeat that a thousand times, just to be sure. Sounds good? That’s exactly what property-based testing has to offer. I’ll show how to get started with this kind of testing, using jqwik (https://jqwik.net/) as an example. But isn’t it all too good to be true, surely there’s some fine print? Of course, there is. I’ll cover that as well.

Difficulty level: mid

Language: PL

Speaker: Magda Stożek

Software developer at SoftwareMill devoted to doing things ‘the right way’. After hours, leader of Zielona Góra JUG and co-organiser of the Greenfield Conference. After even more hours, she enjoys biking, tap dancing and reading long books.

2. Event Sourcing - what could possibly go wrong?

Yet another presentation about Event Sourcing? Yes and no. Event Sourcing is a really great concept. Some could say it's a Holy Grail of the software architecture. I might agree with that, while remembering that everything comes with a price. This session is a summary of my experience with ES gathered while working on 3 different commercial products. Instead of theoretical aspects, I will focus on possible challenges with ES implementation based on Akka Persistence library. What could explode (very often with delayed ignition)? How and where to store events effectively? What are possible schema evolution solutions? How to achieve the highest level of scalability and live with eventual consistency? And many other interesting topics that you might face when experimenting with ES.

Difficulty level: mid

Language: PL

Speaker: Andrzej Ludwikowski

Software Journeyman with over 9 years of experience in commercial software development. Conference speaker and open source contributor. Devotee of DDD, Event Sourcing and Polyglot Persistence. System performance bottlenecks validator. Continuously chasing the dream of a perfect software architecture, fulfilling all of the requirements and trends, even the strangest ones.

Currently one of the Millers at SoftwareMill.