Kotlin

Kotlin Engineering

Technical articles on Kotlin, its runtime, coroutines, and architectural practices.

Testing Philosophy in Kotlin: Expect/Actual, Unit Tests, Kotest, Junit and the Nature of Test Doubles

A deep dive into the philosophical foundation of testing in Kotlin: the meaning behind expect/actual, differences between Unit and JUnit tests, and the conceptual roles of mocks, stubs, fakes, and spies. Understanding tests not as scripts, but as controlled simulations of reality.