diff --git a/velox/exec/prefixsort/CMakeLists.txt b/velox/exec/prefixsort/CMakeLists.txt
index 767d312e2ac3..aac7db501ecd 100644
--- a/velox/exec/prefixsort/CMakeLists.txt
+++ b/velox/exec/prefixsort/CMakeLists.txt
@@ -14,6 +14,8 @@
 
 if(${VELOX_BUILD_TESTING})
   add_subdirectory(tests)
+elseif(${VELOX_BUILD_TEST_UTILS})
+  add_subdirectory(tests/utils)
 endif()
 
 if(${VELOX_ENABLE_BENCHMARKS})
diff --git a/velox/exec/prefixsort/PrefixSortEncoder.h b/velox/exec/prefixsort/PrefixSortEncoder.h
index 151f74c3b5b9..d8a0cd8c923f 100644
--- a/velox/exec/prefixsort/PrefixSortEncoder.h
+++ b/velox/exec/prefixsort/PrefixSortEncoder.h
@@ -32,8 +32,6 @@ class PrefixSortEncoder {
   /// 2. Encoding is compatible with sorting ascending with no nulls.
   template <typename T>
   static FOLLY_ALWAYS_INLINE void encode(T value, char* row);
-  template <typename T>
-  static FOLLY_ALWAYS_INLINE void decode(char* row);
 
  private:
   FOLLY_ALWAYS_INLINE static uint8_t flipSignBit(uint8_t byte) {
@@ -53,27 +51,4 @@ FOLLY_ALWAYS_INLINE void PrefixSortEncoder::encode(int64_t value, char* row) {
   row[0] = flipSignBit(row[0]);
 }
 
-template <>
-FOLLY_ALWAYS_INLINE void PrefixSortEncoder::decode<int64_t>(char* row) {
-  row[0] = flipSignBit(row[0]);
-  const auto v = __builtin_bswap64(*reinterpret_cast<uint64_t*>(row));
-  simd::memcpy(row, &v, sizeof(int64_t));
-}
-
-/// For testing only.
-namespace {
-template <typename T>
-FOLLY_ALWAYS_INLINE void testingEncodeInPlace(const std::vector<T>& data) {
-  for (auto i = 0; i < data.size(); i++) {
-    PrefixSortEncoder::encode(data[i], (char*)data.data() + i * sizeof(T));
-  }
-}
-
-template <typename T>
-FOLLY_ALWAYS_INLINE void testingDecodeInPlace(const std::vector<T>& data) {
-  for (auto i = 0; i < data.size(); i++) {
-    PrefixSortEncoder::decode<T>((char*)data.data() + i * sizeof(T));
-  }
-}
-} // namespace
 } // namespace facebook::velox::exec::prefixsort
diff --git a/velox/exec/prefixsort/benchmarks/CMakeLists.txt b/velox/exec/prefixsort/benchmarks/CMakeLists.txt
index 2f5119b4492a..7d29a84f520d 100644
--- a/velox/exec/prefixsort/benchmarks/CMakeLists.txt
+++ b/velox/exec/prefixsort/benchmarks/CMakeLists.txt
@@ -13,5 +13,6 @@
 # limitations under the License.
 add_executable(velox_prefix_sort_algorithm_benchmark
                PrefixSortAlgorithmBenchmark.cpp)
-target_link_libraries(velox_prefix_sort_algorithm_benchmark
-                      velox_vector_test_lib ${FOLLY_BENCHMARK})
+target_link_libraries(
+  velox_prefix_sort_algorithm_benchmark velox_exec_prefixsort_test_lib
+  velox_vector_test_lib ${FOLLY_BENCHMARK})
diff --git a/velox/exec/prefixsort/benchmarks/PrefixSortAlgorithmBenchmark.cpp b/velox/exec/prefixsort/benchmarks/PrefixSortAlgorithmBenchmark.cpp
index f65bc18c6e74..87c1c33bc21d 100644
--- a/velox/exec/prefixsort/benchmarks/PrefixSortAlgorithmBenchmark.cpp
+++ b/velox/exec/prefixsort/benchmarks/PrefixSortAlgorithmBenchmark.cpp
@@ -17,7 +17,7 @@
 #include <folly/init/Init.h>
 #include "velox/buffer/Buffer.h"
 #include "velox/exec/prefixsort/PrefixSortAlgorithm.h"
-#include "velox/exec/prefixsort/PrefixSortEncoder.h"
+#include "velox/exec/prefixsort/tests/utils/EncoderTestUtils.h"
 
 DEFINE_int32(sort_data_seed, 1, "random test data generate seed.");
 
@@ -49,7 +49,7 @@ class PrefixSortAlgorithmBenchmark {
     std::generate(randomTestVec.begin(), randomTestVec.end(), [&]() {
       return folly::Random::rand64(rng_);
     });
-    prefixsort::testingEncodeInPlace(randomTestVec);
+    prefixsort::test::encodeInPlace(randomTestVec);
     return randomTestVec;
   }
 
diff --git a/velox/exec/prefixsort/tests/CMakeLists.txt b/velox/exec/prefixsort/tests/CMakeLists.txt
index eddfa56d0502..2ce2b2e9975b 100644
--- a/velox/exec/prefixsort/tests/CMakeLists.txt
+++ b/velox/exec/prefixsort/tests/CMakeLists.txt
@@ -11,6 +11,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+add_subdirectory(utils)
+
 add_executable(velox_exec_prefixsort_test PrefixSortAlgorithmTest.cpp)
 
 add_test(
@@ -20,4 +22,5 @@ add_test(
 
 set_tests_properties(velox_exec_prefixsort_test PROPERTIES TIMEOUT 3000)
 
-target_link_libraries(velox_exec_prefixsort_test velox_vector_test_lib)
+target_link_libraries(velox_exec_prefixsort_test velox_exec_prefixsort_test_lib
+                      velox_vector_fuzzer velox_vector_test_lib)
diff --git a/velox/exec/prefixsort/tests/PrefixSortAlgorithmTest.cpp b/velox/exec/prefixsort/tests/PrefixSortAlgorithmTest.cpp
index fdeccf6e4bfe..f379561b140f 100644
--- a/velox/exec/prefixsort/tests/PrefixSortAlgorithmTest.cpp
+++ b/velox/exec/prefixsort/tests/PrefixSortAlgorithmTest.cpp
@@ -20,6 +20,7 @@
 
 #include "velox/exec/prefixsort/PrefixSortAlgorithm.h"
 #include "velox/exec/prefixsort/PrefixSortEncoder.h"
+#include "velox/exec/prefixsort/tests/utils/EncoderTestUtils.h"
 #include "velox/vector/tests/VectorTestUtils.h"
 
 namespace facebook::velox::exec::prefixsort::test {
@@ -43,14 +44,14 @@ class PrefixSortAlgorithmTest : public testing::Test,
       uint32_t entrySize = sizeof(int64_t);
       auto swapBuffer = AlignedBuffer::allocate<char>(entrySize, pool());
       PrefixSortRunner sortRunner(entrySize, swapBuffer->asMutable<char>());
-      testingEncodeInPlace(data1);
+      encodeInPlace(data1);
       sortRunner.quickSort(
           start, end, [&](char* a, char* b) { return memcmp(a, b, 8); });
     }
 
     // Sort data2 with std::sort.
     std::sort(data2.begin(), data2.end());
-    testingDecodeInPlace(data1);
+    decodeInPlace(data1);
     ASSERT_EQ(data1, data2);
   }
 
@@ -75,7 +76,7 @@ TEST_F(PrefixSortAlgorithmTest, testingMedian3) {
   std::generate(
       data1.begin(), data1.end(), [&]() { return folly::Random::rand64(); });
   std::vector<int64_t> data2(data1);
-  testingEncodeInPlace(data1);
+  encodeInPlace(data1);
 
   size_t entrySize = sizeof(int64_t);
   auto ptr1 = (char*)data1.data();
@@ -85,7 +86,7 @@ TEST_F(PrefixSortAlgorithmTest, testingMedian3) {
       ptr1, ptr2, ptr3, entrySize, [&](char* a, char* b) {
         return memcmp(a, b, entrySize);
       });
-  testingDecodeInPlace(data1);
+  decodeInPlace(data1);
   auto median = *(reinterpret_cast<int64_t*>(medianPtr));
   // Sort the input vector data, the middle element must be equal to the
   // median we calculated.
diff --git a/velox/exec/prefixsort/tests/utils/CMakeLists.txt b/velox/exec/prefixsort/tests/utils/CMakeLists.txt
new file mode 100644
index 000000000000..c4691246a33f
--- /dev/null
+++ b/velox/exec/prefixsort/tests/utils/CMakeLists.txt
@@ -0,0 +1,17 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+add_library(velox_exec_prefixsort_test_lib EncoderTestUtils.cpp)
+
+target_link_libraries(velox_exec_prefixsort_test_lib velox_vector_test_lib)
diff --git a/velox/exec/prefixsort/tests/utils/EncoderTestUtils.cpp b/velox/exec/prefixsort/tests/utils/EncoderTestUtils.cpp
new file mode 100644
index 000000000000..e475364d2607
--- /dev/null
+++ b/velox/exec/prefixsort/tests/utils/EncoderTestUtils.cpp
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "velox/exec/prefixsort/tests/utils/EncoderTestUtils.h"
+
+namespace facebook::velox::exec::prefixsort::test {
+
+namespace {
+
+/// The decode method will only be used in testing scenarios. In production
+/// code, we have no scenarios that require decoding a normalized key.
+void decodeNoNulls(char* encoded, int64_t& value) {
+  value = *reinterpret_cast<uint64_t*>(encoded);
+  value = __builtin_bswap64(value ^ 128);
+}
+
+} // namespace
+
+void encodeInPlace(std::vector<int64_t>& data) {
+  for (auto i = 0; i < data.size(); i++) {
+    PrefixSortEncoder::encode(
+        data[i], (char*)data.data() + i * sizeof(int64_t));
+  }
+}
+
+void decodeInPlace(std::vector<int64_t>& data) {
+  for (auto i = 0; i < data.size(); i++) {
+    decodeNoNulls((char*)data.data() + i * sizeof(int64_t), data[i]);
+  }
+}
+
+} // namespace facebook::velox::exec::prefixsort::test
diff --git a/velox/exec/prefixsort/tests/utils/EncoderTestUtils.h b/velox/exec/prefixsort/tests/utils/EncoderTestUtils.h
new file mode 100644
index 000000000000..65da5d89a794
--- /dev/null
+++ b/velox/exec/prefixsort/tests/utils/EncoderTestUtils.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#pragma once
+
+#include "velox/exec/prefixsort/PrefixSortEncoder.h"
+
+namespace facebook::velox::exec::prefixsort::test {
+
+/// Replace the elements in data with encoded ones(compatible with sorting in
+/// ascending order), assuming that the elements in data are all non-null.
+void encodeInPlace(std::vector<int64_t>& data);
+
+/// Replace the elements in data with decoded ones, assuming that the elements
+/// in data are all non-null and encoded(compatible with sorting in ascending
+/// order).
+void decodeInPlace(std::vector<int64_t>& data);
+
+} // namespace facebook::velox::exec::prefixsort::test