fix checkpoint test and checkstyle polish

Author: simonbasle

spring-context/src/main/java/org/springframework/scheduling/annotation/ScheduledAnnotationReactiveSupport.java

@@ -57,7 +57,7 @@ static class ReactiveTask {
 		private final Duration initialDelay;
 		private final Duration otherDelay;
 		private final boolean isFixedRate;
-		private final String checkpoint;
+		protected final String checkpoint;
 		private final Disposable.Swap disposable;
 
 		private final Log logger = LogFactory.getLog(getClass());

spring-context/src/test/java/org/springframework/scheduling/annotation/ScheduledAnnotationReactiveSupportTests.java

@@ -21,7 +21,6 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import org.awaitility.Awaitility;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
@@ -238,11 +237,10 @@ void monoErrorHasCheckpoint() throws InterruptedException {
 			final ScheduledAnnotationReactiveSupport.ReactiveTask reactiveTask = new ScheduledAnnotationReactiveSupport.ReactiveTask(
 					m, target, Duration.ZERO, Duration.ofSeconds(10), true);
 
-			reactiveTask.subscribe();
-			Thread.sleep(500);
-
-			reactiveTask.cancel();
+			assertThat(reactiveTask.checkpoint).isEqualTo("@Scheduled 'org.springframework.scheduling.annotation"
+					+ ".ScheduledAnnotationReactiveSupportTests$ReactiveMethods#monoError()'"
+					+ " [ScheduledAnnotationReactiveSupport]");
 		}
 
 	}
-}
+}