When writing unit tests, we often need to set up representative test data. Sometimes we rely on mocks as it is “easier” or we spend time inputting data manually and suffer the cost of future maintenance. Either way, we usually only cover one path through our app based on assumptions of how our code currently works.

What if it were possible to generate your test data using real objects without hard coding fixed values? Today we will look at using random values through “constrained non-determinism” - what it is, why use it, and the new KotlinFixture library.