Testing Domain Invariants with Property-Based Testing

Friday afternoon 14:00 - 16:00 CET (UTC+1)


Hadi Ahmadi and Sepehr Namdar


The first step in developing a domain model, is to analyze the problem and then break it up into smaller parts. TDD is a great technique that many developers use for this purpose. Most developers use example-based approach for writing their tests and don’t consider other methods.

Property-based testing requires us to approach testing differently from what we’re used to. In property-based testing, you write tests not by specifying examples, but by describing the rules and properties and generating the examples automatically.

In this hands-on, we write property-based tests for an object-oriented domain model, TDD style, and explore the way of breaking down invariants into smaller parts and develop in small increments. The purpose of the workshop is to show attendees how they can use property-based testing as a tool for exploring the problem domain and invariants more in-depth and develop in small steps.

In this sessions, we will:

  • Explain Property-Based Testing
  • Explain the ways of writing properties
  • Describe a problem to implement
  • Break down invariants into smaller parts
  • Writing Properties first
  • Implementing domain model to pass the tests

The examples will be available in Java and C#.

About Hadi Ahmadi

Independent Software Architect, Consultant, DDD Teacher, Co-Founder of DDD Iran Community Twitter LinkedIn

With over 10 years of experience in Software development, I am a Technical Leader, Architect and Designer. Passionate for Software design & Architecture (specially DDD, CQRS & Event Sourcing) and Agile practices such as TDD and BDD with an in depth knowledge of OOP, GoF Design Patterns, SOLID Principles and Integration Patterns.

About Sepehr Namdar

Technology agnostic developer, DDD Iran organiser and DDD Teacher Twitter LinkedIn Company Website GitHub

Interested in Agile practices, Craft and Architecture and having had the opportunity to work in various development teams, I acquired the knowledge on all phases of software development. I believe that the sucess of a product (i.e. software) does not depend on technologies that we use but a good understanding of business needs and on the methodologies applied during its development.