KAFKA-14132: Replace Easymock & Powermock with Mockito in KafkaBasedLogTest

build.gradle

@@ -417,7 +417,7 @@ subprojects {
       // connect tests
       "**/DistributedHerderTest.*",
       "**/KafkaConfigBackingStoreTest.*",
-      "**/KafkaBasedLogTest.*", "**/StandaloneHerderTest.*",
+      "**/StandaloneHerderTest.*",
       "**/WorkerSinkTaskTest.*", "**/WorkerSinkTaskThreadedTest.*"
     ])
   }

connect/runtime/src/main/java/org/apache/kafka/connect/util/KafkaBasedLog.java

@@ -102,8 +102,8 @@ public class KafkaBasedLog<K, V> {
     private Consumer<K, V> consumer;
     private Optional<Producer<K, V>> producer;
     private TopicAdmin admin;
-
-    private Thread thread;
+    // Visible for testing
+    Thread thread;
     private boolean stopRequested;
     private final Queue<Callback<Void>> readLogEndOffsetCallbacks;
     private final java.util.function.Consumer<TopicAdmin> initializer;