diff --git a/extensions-core/multi-stage-query/src/test/java/org/apache/druid/msq/statistics/DelegateOrMinKeyCollectorTest.java b/extensions-core/multi-stage-query/src/test/java/org/apache/druid/msq/statistics/DelegateOrMinKeyCollectorTest.java
index f5a07de1af5..09b52a37157 100644
--- a/extensions-core/multi-stage-query/src/test/java/org/apache/druid/msq/statistics/DelegateOrMinKeyCollectorTest.java
+++ b/extensions-core/multi-stage-query/src/test/java/org/apache/druid/msq/statistics/DelegateOrMinKeyCollectorTest.java
@@ -20,6 +20,7 @@
 package org.apache.druid.msq.statistics;
 
 import com.google.common.collect.ImmutableList;
+import org.apache.druid.common.config.NullHandling;
 import org.apache.druid.frame.key.ClusterBy;
 import org.apache.druid.frame.key.KeyTestUtils;
 import org.apache.druid.frame.key.RowKey;
@@ -41,6 +42,10 @@ public class DelegateOrMinKeyCollectorTest
   private final RowSignature signature = RowSignature.builder().add("x", ColumnType.LONG).build();
   private final Comparator<RowKey> comparator = clusterBy.keyComparator();
 
+  static {
+    NullHandling.initializeForTests();
+  }
+
   @Test
   public void testEmpty()
   {
diff --git a/extensions-core/multi-stage-query/src/test/java/org/apache/druid/msq/statistics/QuantilesSketchKeyCollectorTest.java b/extensions-core/multi-stage-query/src/test/java/org/apache/druid/msq/statistics/QuantilesSketchKeyCollectorTest.java
index 0555c7c5d55..974f79c7bfb 100644
--- a/extensions-core/multi-stage-query/src/test/java/org/apache/druid/msq/statistics/QuantilesSketchKeyCollectorTest.java
+++ b/extensions-core/multi-stage-query/src/test/java/org/apache/druid/msq/statistics/QuantilesSketchKeyCollectorTest.java
@@ -20,6 +20,7 @@
 package org.apache.druid.msq.statistics;
 
 import com.google.common.collect.ImmutableList;
+import org.apache.druid.common.config.NullHandling;
 import org.apache.druid.frame.key.ClusterBy;
 import org.apache.druid.frame.key.ClusterByPartition;
 import org.apache.druid.frame.key.ClusterByPartitions;
@@ -41,6 +42,10 @@ public class QuantilesSketchKeyCollectorTest
   private final Comparator<RowKey> comparator = clusterBy.keyComparator();
   private final int numKeys = 500_000;
 
+  static {
+    NullHandling.initializeForTests();
+  }
+
   @Test
   public void test_empty()
   {