Kenny Baas-Schwegler

Kenny Baas-Schwegler

Domain Whisperer and Software Consultant
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· Crunching 'real-life stories' with DDD EventStorming and combining it with BDD techniques
· EventStorming and Example Mapping
· Leverage Domain-Driven Design throughout testing


Kenny Baas is a Software Engineer and Consultant focusing on software quality at Xebia. He mentors and coaches teams by using practices and techniques from Domain Driven Design, Behaviour Driven Development, Test Driven Development, and Continuous Delivery.

He is an advocate for multidisciplinary collaboration in open spaces. By using techniques such as Event Storming, and Example Mapping, he helps engineer requirements to design and model software. With these methods, he aims to create a transparent, collaborative domain space with constant and instant feedback when delivering software.

Besides his daily work, he also helps organise meetups for Behaviour Driven Development NL and Domain Driven Design Nederland.

Crunching 'real-life stories' with DDD EventStorming and combining it with BDD techniques (Workshop)

To really understand what our users will need, we want to have a first-hand experience from 'real-life stories' before we can model and create our software. While both the DDD and BDD techniques emphasis on ‘real-life stories’ by doing collaborative deliberate learning, they both focus on different goals. DDD focuses more on creating bounded contexts in which a single model is created, BDD focuses more on different scenarios and can create executable specifications as an outcome. By doing EventStorming and using techniques from BDD based on feature mapping, such as Example Mapping, we can create more insights. We can simultaneously create a model and executable specifications for our user needs. This way, we can write software and tests which matches the shared understanding of the user, creating a ubiquitous language. Value will be shipped at a faster pace.

In this hands-on session, we start with a Process EventStorming. We will use Example Mapping to get more insights into our process. Eventually, I will show you how the outcome can drive our Software Modelling EventStorming and create Executable Specifications. This way we can create a ubiquitous domain language that we can use in our application and test code. You don't need a laptop for this session as the focus is on the discovery phase.

EventStorming and Example Mapping (Workshop)

Creating multiple models for the same problem is one of the more important lessons that Domain Driven Design teaches us. It is a lot cheaper to quickly iterate over them and throw away less useful prototypes before we even start coding. However, creating multiple models can be hard. When we begin gaining insight from our domain, we suffer a lot from cognitive biases that get in our way to gain new insights. We need these insights before we even start thinking about modelling. Tools like event storming and example mapping can help us to deliberate discover, and battle these biases. They help you quickly gain insight into the problem space. But the fallacy here is that we can get locked into the tool, and get stuck again.

What you will learn
In this two day workshop, you will learn the essentials of event storming and how it can help you gain the necessary insights you need to deliver quality software. With our newly acquired domain knowledge, we can then start exploring the solution space. During the exploration, we begin to design and model multiple models for the same problem with Domain Driven Design patterns. This way of visualising gives us the power to quickly iterate over the different models and figure out which model will be the best to use for now. Eventually, we start our coding journey TDD style, iterating over the model to refactor towards deeper insights while discovering how hexagonal architecture may help us to protect our domain code from the technical concerns, in the long run.

Is this workshop right for me?
Yes, if you are a software architect
Yes, if you are a software developer

Domain Driven Design a brief tour
Event Storming - essential workshop
Example Mapping - essential workshop
Discovery Phase: Process Modeling Event Storming / Example Mapping

Technical DDD patterns
Software modelling
Test-first coding flow (from problem space to solution space)
Hexagonal architecture overview and implementation
Refactor towards deeper insights

Read the free ebook The Anatomy Of Domain-Driven Design:
It is nice to have read Domain Driven Design by Eric Evans (the blue book), it is not required.
Able to properly remove a sticky note
For the second day: Bring a laptop with your favourite IDE and programming language

Leverage Domain-Driven Design throughout testing (Workshop)

Every time I start working on a new software product I want to learn the domain. The faster I learn the domain I am working in, the faster I will add value to that product. I always start by looking at the tests; they should reflect what the software is built for and how it needs to behave.

However, the tests seldom reflect the same language as the code, the documentation and the communication. Inconsistent language usually is one of the reasons testing slows down the software delivery process. A lot of ‘ping-pong’ going on between several disciplines and even though the product is rigorously tested, there are still a lot of bugs found in production. It is hard, or even impossible to build the right product if there is inconsistency in the language used to communicate.

Join me in this talk where I will show you how to leverage Domain-Driven Design throughout testing. You will learn how to make the language of your tests consistent with the communication used, and create tests that can serve as living documentation.

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