diff --git a/velox/exec/tests/utils/PlanBuilder.cpp b/velox/exec/tests/utils/PlanBuilder.cpp
index aacedfd75c2b..2b07f9b06213 100644
--- a/velox/exec/tests/utils/PlanBuilder.cpp
+++ b/velox/exec/tests/utils/PlanBuilder.cpp
@@ -988,6 +988,16 @@ PlanBuilder& PlanBuilder::partitionedOutputBroadcast(
   return *this;
 }
 
+PlanBuilder& PlanBuilder::partitionedOutputArbitrary(
+    const std::vector<std::string>& outputLayout) {
+  auto outputType = outputLayout.empty()
+      ? planNode_->outputType()
+      : extract(planNode_->outputType(), outputLayout);
+  planNode_ = core::PartitionedOutputNode::arbitrary(
+      nextPlanNodeId(), outputType, planNode_);
+  return *this;
+}
+
 PlanBuilder& PlanBuilder::localPartition(
     const std::vector<std::string>& keys,
     const std::vector<core::PlanNodePtr>& sources) {
diff --git a/velox/exec/tests/utils/PlanBuilder.h b/velox/exec/tests/utils/PlanBuilder.h
index adb7983b0999..076435e67501 100644
--- a/velox/exec/tests/utils/PlanBuilder.h
+++ b/velox/exec/tests/utils/PlanBuilder.h
@@ -560,7 +560,7 @@ class PlanBuilder {
       core::PartitionFunctionSpecPtr partitionFunctionSpec,
       const std::vector<std::string>& outputLayout = {});
 
-  /// Add a PartitionedOutputNode to broadcast the input data.
+  /// Adds a PartitionedOutputNode to broadcast the input data.
   ///
   /// @param outputLayout Optional output layout in case it is different then
   /// the input. Output columns may appear in different order from the input,
@@ -569,7 +569,11 @@ class PlanBuilder {
   PlanBuilder& partitionedOutputBroadcast(
       const std::vector<std::string>& outputLayout = {});
 
-  /// Add a LocalPartitionNode to hash-partition the input on the specified
+  /// Adds a PartitionedOutputNode to put data into arbitrary buffer.
+  PlanBuilder& partitionedOutputArbitrary(
+      const std::vector<std::string>& outputLayout = {});
+
+  /// Adds a LocalPartitionNode to hash-partition the input on the specified
   /// keys using exec::HashPartitionFunction. Number of partitions is determined
   /// at runtime based on parallelism of the downstream pipeline.
   ///