diff --git a/core/src/test/scala/unit/kafka/utils/TestUtils.scala b/core/src/test/scala/unit/kafka/utils/TestUtils.scala
index 9616f89c467..46b8df0c6c1 100755
--- a/core/src/test/scala/unit/kafka/utils/TestUtils.scala
+++ b/core/src/test/scala/unit/kafka/utils/TestUtils.scala
@@ -1341,10 +1341,12 @@ object TestUtils extends Logging {
   // Note: Call this method in the test itself, rather than the @AfterEach method.
   // Because of the assert, if assertNoNonDaemonThreads fails, nothing after would be executed.
   def assertNoNonDaemonThreads(threadNamePrefix: String): Unit = {
-    val threadCount = Thread.getAllStackTraces.keySet.asScala.count { t =>
+    val nonDaemonThreads = Thread.getAllStackTraces.keySet.asScala.filter { t =>
       !t.isDaemon && t.isAlive && t.getName.startsWith(threadNamePrefix)
     }
-    assertEquals(0, threadCount)
+
+    val threadCount = nonDaemonThreads.size
+    assertEquals(0, threadCount, s"Found unexpected $threadCount NonDaemon threads=${nonDaemonThreads.map(t => t.getName).mkString(", ")}")
   }
 
   def allThreadStackTraces(): String = {