In the ScrollBarTest class, the often cited example of Compose Desktop testing that is not Android code, there are the following lines:

// don't inline, surface controls canvas life time

private val surface = Surface.makeRasterN32Premul(100, 100)

private val canvas = surface.canvas

What's this code doing in terms of facilitating JVM Compose testing?

Where do you see that code at https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/[…]sktopTest/kotlin/androidx/compose/foundation/ScrollbarTest.kt ?

Fascinating. Your link does not show the code. My link: https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/[…]ScrollbarTest.kt;drc=68ebfa11f81d57ba35ccb073b97d06c2399d8496 does show the code at lines 71-73. I'm guessing your link is more recent that the one I was using which, if memory serves, I got from the original bug report post. I like your link better because it means the answer to my question is: nothing at all.