@Test
    fun test_main_scheduler_subscription() {
        val emitted = 10
        val upstream = observable<Int> {
            it.onNext(emitted)
        }.subscribeOn(mainScheduler)
        upstream.subscribe {
            assertEquals(emitted, it)
        }
    }

globalThis

window

jsNodeTest

@Test
fun submits_task_to_executor() {
    val scheduler = MainScheduler()
    val executor = scheduler.newExecutor()
    executor.submit {}
}

jsBrowserTest

jsNodeTest

Submitting 0
[error] ReferenceError: window is not defined