Fixes

kotlinx-coroutines-test/common/src/DelayController.kt

@@ -84,11 +84,11 @@ public interface DelayController {
     /**
      * Call after test code completes to ensure that the dispatcher is properly cleaned up.
      *
-     * @throws UncompletedCoroutinesError if any pending tasks are active, however it will not throw for suspended
+     * @throws AssertionError if any pending tasks are active, however it will not throw for suspended
      * coroutines.
      */
     @ExperimentalCoroutinesApi
-    @Throws(UncompletedCoroutinesError::class)
+    @Throws(AssertionError::class)
     public fun cleanupTestCoroutines()
 
     /**
@@ -123,13 +123,6 @@ public interface DelayController {
     public fun resumeDispatcher()
 }
 
-/**
- * Thrown when a test has completed and there are tasks that are not completed or cancelled.
- */
-// todo: maybe convert into non-public class in 1.3.0 (need use-cases for a public exception type)
-@ExperimentalCoroutinesApi
-public class UncompletedCoroutinesError(message: String): AssertionError(message)
-
 internal interface SchedulerAsDelayController: DelayController {
     public val scheduler: TestCoroutineScheduler
 

kotlinx-coroutines-test/common/src/TestBuilders.kt

@@ -34,7 +34,7 @@ import kotlin.coroutines.*
  *
  * Unhandled exceptions thrown by coroutines in the test will be re-thrown at the end of the test.
  *
- * @throws UncompletedCoroutinesError If the [testBody] does not complete (or cancel) all coroutines that it launches
+ * @throws AssertionError If the [testBody] does not complete (or cancel) all coroutines that it launches
  * (including coroutines suspended on join/await).
  *
  * @param context additional context elements. If [context] contains [CoroutineDispatcher] or [CoroutineExceptionHandler],

kotlinx-coroutines-test/common/src/TestCoroutineScheduler.kt

@@ -24,10 +24,11 @@ import kotlin.jvm.*
  */
 @ExperimentalCoroutinesApi
 // TODO: maybe make this a `TimeSource`?
-public class TestCoroutineScheduler: AbstractCoroutineContextElement(TestCoroutineScheduler), CoroutineContext.Element {
+public class TestCoroutineScheduler : AbstractCoroutineContextElement(TestCoroutineScheduler),
+    CoroutineContext.Element {
 
     /** @suppress */
-    public companion object Key: CoroutineContext.Key<TestCoroutineScheduler>
+    public companion object Key : CoroutineContext.Key<TestCoroutineScheduler>
 
     /** This heap stores the knowledge about which dispatchers are interested in which moments of virtual time. */
     // TODO: all the synchronization is done via a separate lock, so a non-thread-safe priority queue can be used.
@@ -55,7 +56,7 @@ public class TestCoroutineScheduler: AbstractCoroutineContextElement(TestCorouti
         dispatcher: TestDispatcher,
         timeDeltaMillis: Long,
         marker: T,
-        isCancelled : (T) -> Boolean
+        isCancelled: (T) -> Boolean
     ): DisposableHandle {
         require(timeDeltaMillis >= 0) { "Attempted scheduling an event earlier in time (with the time delta $timeDeltaMillis)" }
         val count = count.getAndIncrement()

kotlinx-coroutines-test/common/src/TestCoroutineScope.kt

@@ -11,13 +11,13 @@ import kotlin.coroutines.*
  * A scope which provides detailed control over the execution of coroutines for tests.
  */
 @ExperimentalCoroutinesApi
-public interface TestCoroutineScope: CoroutineScope, UncaughtExceptionCaptor {
+public sealed interface TestCoroutineScope: CoroutineScope, UncaughtExceptionCaptor {
     /**
      * Call after the test completes.
      * Calls [UncaughtExceptionCaptor.cleanupTestCoroutinesCaptor] and [DelayController.cleanupTestCoroutines].
      *
      * @throws Throwable the first uncaught exception, if there are any uncaught exceptions.
-     * @throws UncompletedCoroutinesError if any pending tasks are active, however it will not throw for suspended
+     * @throws AssertionError if any pending tasks are active, however it will not throw for suspended
      * coroutines.
      */
     @ExperimentalCoroutinesApi
@@ -28,8 +28,6 @@ public interface TestCoroutineScope: CoroutineScope, UncaughtExceptionCaptor {
      */
     @ExperimentalCoroutinesApi
     public val testScheduler: TestCoroutineScheduler
-        get() = coroutineContext[TestCoroutineScheduler]
-            ?: throw UnsupportedOperationException("This scope does not have a TestCoroutineScheduler linked to it")
 }
 
 private class TestCoroutineScopeImpl (
@@ -158,3 +156,9 @@ public fun TestCoroutineScope.resumeDispatcher() {
 private val TestCoroutineScope.delayControllerForPausing: DelayController
     get() = coroutineContext.delayController
         ?: throw IllegalStateException("This scope isn't able to pause its dispatchers")
+
+/**
+ * Thrown when a test has completed and there are tasks that are not completed or cancelled.
+ */
+@ExperimentalCoroutinesApi
+internal class UncompletedCoroutinesError(message: String): AssertionError(message)

kotlinx-coroutines-test/common/src/TestDispatcher.kt

@@ -18,7 +18,6 @@ public abstract class TestDispatcher: CoroutineDispatcher(), Delay {
     public abstract val scheduler: TestCoroutineScheduler
 
     /** Notifies the dispatcher that it should process a single event marked with [marker] happening at time [time]. */
-    @ExperimentalCoroutinesApi
     internal abstract fun processEvent(time: Long, marker: Any)
 
     /** @suppress */