diff --git a/core/src/test/java/org/opensearch/sql/planner/physical/collector/RoundingTest.java b/core/src/test/java/org/opensearch/sql/planner/physical/collector/RoundingTest.java
index 4f6d51c901..467a4e1abf 100644
--- a/core/src/test/java/org/opensearch/sql/planner/physical/collector/RoundingTest.java
+++ b/core/src/test/java/org/opensearch/sql/planner/physical/collector/RoundingTest.java
@@ -57,6 +57,10 @@ void datetime_rounding_non_core_type_span() {
         DSL.span(DSL.ref("timestamp", new MockTimestampExprType()), DSL.literal(1), "h");
     rounding = Rounding.createRounding(timestampSpan);
     assertInstanceOf(Rounding.TimestampRounding.class, rounding);
+    SpanExpression datetimeSpan =
+        DSL.span(DSL.ref("datetime", new MockDateTimeExprType()), DSL.literal(1), "h");
+    rounding = Rounding.createRounding(datetimeSpan);
+    assertInstanceOf(Rounding.DatetimeRounding.class, rounding);
   }
 
   @Test
@@ -95,4 +99,11 @@ public String typeName() {
       return "TIMESTAMP";
     }
   }
+
+  static class MockDateTimeExprType implements ExprType {
+    @Override
+    public String typeName() {
+      return "DATETIME";
+    }
+  }
 }