The Ktor version was updated from 2.3.12 -> 3.0.1. After fixing compilation-related errors I tried to run some of the tests, but problems arose that were not there before.

class kotlinx.coroutines.test.TestCoroutineScheduler$timeSource$1 cannot be cast to class kotlin.time.TimeSource$WithComparableMarks (kotlinx.coroutines.test.TestCoroutineScheduler$timeSource$1 and kotlin.time.TimeSource$WithComparableMarks are in unnamed module of loader 'app')
java.lang.ClassCastException: class kotlinx.coroutines.test.TestCoroutineScheduler$timeSource$1 cannot be cast to class kotlin.time.TimeSource$WithComparableMarks (kotlinx.coroutines.test.TestCoroutineScheduler$timeSource$1 and kotlin.time.TimeSource$WithComparableMarks are in unnamed module of loader 'app')

In the test, I have:

@Test
fun `should return foo`() = testApplication {
   block()
}