I was using Kotlin Coroutines version

1.6.4

in my project, after adding a library with dependency to Kotlin Coroutines

1.7.0-Beta

, tests using

runTest

started failing because of

backgroundScope

premature cancellation, the problem was gone after updating this project Kotlin Coroutines version to

1.7.0-Beta

. Can anyone explain it to me?

runTest

was reworked quite a bit for

1.7.0-Beta

, but there was no intention to change the behavior of

backgroundScope

. Maybe we introduced a bug (or accidentally fixed one). Could you file an issue at https://github.com/Kotlin/kotlinx.coroutines/issues with an example of the code that behaves incorrectly?

That is the strange part: Project use coroutines regular and test 1.6.4 Lib use coroutines 1.7.0-Beta Just adding lib (without using anything from inside) changed runTest behavior

Typically, gradle won't depend on several copies of the same library. Instead, it analyzes all the usages of a library and selects a single version that should suit everyone. In your case,

kotlinx-coroutines-core

would use the upgraded version for the whole project.