LitmusKt: Concurrency Stress Testing for Kotlin

TL;DR

LitmusKt is a novel tool for concurrency testing in Kotlin that supports multiple platforms, enabling detection and fixing of bugs in the Kotlin compiler and integration into CI pipelines.

Contribution

It introduces the first litmus testing tool for Kotlin's multiplatform concurrency, allowing cross-platform bug detection and fixing.

Findings

Discovered and fixed new Kotlin compiler bugs.

Integrated litmus testing into Kotlin's CI pipeline.

Supported testing on Kotlin/Native and Kotlin/JVM.

Abstract

We present LitmusKt - the first tool for litmus testing concurrent programs in Kotlin. The tool's novelty also lies in the fact that Kotlin is a multiplatform language, i.e., it compiles into multiple platforms, which means that the concurrency has to be tested on several of them. Our tool allows writing litmus tests in a single custom DSL, and these tests are then run in Kotlin/Native and Kotlin/JVM, two main platforms for concurrent programming in Kotlin. Using LitmusKt, we discovered novel bugs in the Kotlin compiler, which we then fixed and they are no longer present. Moreover, LitmusKt was integrated into the CI pipeline for Kotlin. LitmusKt is available on GitHub: https://github.com/JetBrains-Research/litmuskt. The demo is available on YouTube: https://youtu.be/oWCZp_Huwss.