diff --git a/integration-tests/src/main/java/org/apache/druid/testing/clients/OverlordResourceTestClient.java b/integration-tests/src/main/java/org/apache/druid/testing/clients/OverlordResourceTestClient.java
index 5cee2fb2886..f2e600e4264 100644
--- a/integration-tests/src/main/java/org/apache/druid/testing/clients/OverlordResourceTestClient.java
+++ b/integration-tests/src/main/java/org/apache/druid/testing/clients/OverlordResourceTestClient.java
@@ -153,6 +153,11 @@ public class OverlordResourceTestClient
     return getTasks("pendingTasks");
   }
 
+  public List<TaskResponseObject> getCompleteTasksForDataSource(final String dataSource)
+  {
+    return getTasks(StringUtils.format("tasks?state=complete&datasource=%s", StringUtils.urlEncode(dataSource)));
+  }
+
   private List<TaskResponseObject> getTasks(String identifier)
   {
     try {
@@ -233,7 +238,14 @@ public class OverlordResourceTestClient
   {
     try {
       StatusResponseHolder response = httpClient.go(
-          new Request(HttpMethod.POST, new URL(StringUtils.format("%ssupervisor/%s/shutdown", getIndexerURL(), StringUtils.urlEncode(id)))),
+          new Request(
+              HttpMethod.POST,
+              new URL(StringUtils.format(
+                  "%ssupervisor/%s/shutdown",
+                  getIndexerURL(),
+                  StringUtils.urlEncode(id)
+              ))
+          ),
           responseHandler
       ).get();
       if (!response.getStatus().equals(HttpResponseStatus.OK)) {
diff --git a/integration-tests/src/main/java/org/apache/druid/testing/clients/TaskResponseObject.java b/integration-tests/src/main/java/org/apache/druid/testing/clients/TaskResponseObject.java
index 501cd5e1398..38f0a86223e 100644
--- a/integration-tests/src/main/java/org/apache/druid/testing/clients/TaskResponseObject.java
+++ b/integration-tests/src/main/java/org/apache/druid/testing/clients/TaskResponseObject.java
@@ -28,6 +28,7 @@ public class TaskResponseObject
 {
 
   private final String id;
+  private final String type;
   private final DateTime createdTime;
   private final DateTime queueInsertionTime;
   private final TaskState status;
@@ -35,12 +36,14 @@ public class TaskResponseObject
   @JsonCreator
   private TaskResponseObject(
       @JsonProperty("id") String id,
+      @JsonProperty("type") String type,
       @JsonProperty("createdTime") DateTime createdTime,
       @JsonProperty("queueInsertionTime") DateTime queueInsertionTime,
       @JsonProperty("status") TaskState status
   )
   {
     this.id = id;
+    this.type = type;
     this.createdTime = createdTime;
     this.queueInsertionTime = queueInsertionTime;
     this.status = status;
@@ -52,6 +55,12 @@ public class TaskResponseObject
     return id;
   }
 
+  @SuppressWarnings("unused") // Used by Jackson serialization?
+  public String getType()
+  {
+    return type;
+  }
+
   @SuppressWarnings("unused") // Used by Jackson serialization?
   public DateTime getCreatedTime()
   {
diff --git a/integration-tests/src/test/java/org/apache/druid/tests/indexer/AbstractITBatchIndexTest.java b/integration-tests/src/test/java/org/apache/druid/tests/indexer/AbstractITBatchIndexTest.java
index 226824f476f..121fd7a9bda 100644
--- a/integration-tests/src/test/java/org/apache/druid/tests/indexer/AbstractITBatchIndexTest.java
+++ b/integration-tests/src/test/java/org/apache/druid/tests/indexer/AbstractITBatchIndexTest.java
@@ -160,10 +160,25 @@ public class AbstractITBatchIndexTest extends AbstractIndexerTest
   {
     final Set<String> oldVersions = waitForNewVersion ? coordinator.getSegmentVersions(dataSourceName) : null;
 
+    long startSubTaskCount = -1;
+    final boolean assertRunsSubTasks = taskSpec.contains("index_parallel");
+    if (assertRunsSubTasks) {
+      startSubTaskCount = countCompleteSubTasks(dataSourceName);
+    }
+
     final String taskID = indexer.submitTask(taskSpec);
     LOG.info("TaskID for loading index task %s", taskID);
     indexer.waitUntilTaskCompletes(taskID);
 
+    if (assertRunsSubTasks) {
+      final long newSubTasks = countCompleteSubTasks(dataSourceName) - startSubTaskCount;
+      Assert.assertTrue(
+          StringUtils.format(
+              "The supervisor task[%s] didn't create any sub tasks. Was it executed in the parallel mode?",
+              taskID
+          ), newSubTasks > 0);
+    }
+
     // ITParallelIndexTest does a second round of ingestion to replace segements in an existing
     // data source. For that second round we need to make sure the coordinator actually learned
     // about the new segments befor waiting for it to report that all segments are loaded; otherwise
@@ -179,4 +194,12 @@ public class AbstractITBatchIndexTest extends AbstractIndexerTest
         () -> coordinator.areSegmentsLoaded(dataSourceName), "Segment Load"
     );
   }
+
+  private long countCompleteSubTasks(final String dataSource)
+  {
+    return indexer.getCompleteTasksForDataSource(dataSource)
+                  .stream()
+                  .filter(t -> t.getType().equals("index_sub"))
+                  .count();
+  }
 }
diff --git a/integration-tests/src/test/resources/indexer/wikipedia_parallel_index_task.json b/integration-tests/src/test/resources/indexer/wikipedia_parallel_index_task.json
index f317c538f6b..887508ad7e9 100644
--- a/integration-tests/src/test/resources/indexer/wikipedia_parallel_index_task.json
+++ b/integration-tests/src/test/resources/indexer/wikipedia_parallel_index_task.json
@@ -61,6 +61,10 @@
                 "baseDir": "/resources/data/batch_index",
                 "filter": "wikipedia_index_data*"
             }
+        },
+        "tuningConfig": {
+            "type": "index_parallel",
+            "maxNumSubTasks": 10
         }
     }
 }
\ No newline at end of file
diff --git a/integration-tests/src/test/resources/indexer/wikipedia_parallel_reindex_task.json b/integration-tests/src/test/resources/indexer/wikipedia_parallel_reindex_task.json
index c06890bfde4..ef16c648cb8 100644
--- a/integration-tests/src/test/resources/indexer/wikipedia_parallel_reindex_task.json
+++ b/integration-tests/src/test/resources/indexer/wikipedia_parallel_reindex_task.json
@@ -60,6 +60,10 @@
                 "baseDir": "/resources/data/batch_index",
                 "filter": "wikipedia_index_data2*"
             }
+        },
+        "tuningConfig": {
+            "type": "index_parallel",
+            "maxNumSubTasks": 10
         }
     }
 }
\ No newline at end of file