diff --git a/test/vvenc_unit_test/vvenc_unit_test.cpp b/test/vvenc_unit_test/vvenc_unit_test.cpp
index d05a86aa..d88157a9 100644
--- a/test/vvenc_unit_test/vvenc_unit_test.cpp
+++ b/test/vvenc_unit_test/vvenc_unit_test.cpp
@@ -1299,6 +1299,46 @@ static bool check_SAD( RdCost* ref, RdCost* opt, unsigned num_cases, int width,
   return passed;
 }
 
+static bool check_HADs( RdCost* ref, RdCost* opt, unsigned num_cases, int width, int height, bool fast )
+{
+  std::ostringstream sstm;
+  const char* fast_str = fast ? "_fast" : "";
+  sstm << "RdCost::m_afpDistortFunc[0][DF_HAD" << width << fast_str << "] "
+       << " w=" << width << " h=" << height;
+  printf( "Testing %s\n", sstm.str().c_str() );
+
+  DimensionGenerator rng;
+  InputGenerator<Pel> g10{ 10, /*is_signed=*/false };
+
+  bool passed = true;
+  for( unsigned i = 0; i < num_cases; i++ )
+  {
+    int org_stride = rng.get( width, g_fastUnitTest ? 256 : 1024 );
+    int cur_stride = rng.get( width, g_fastUnitTest ? 256 : 1024 );
+    std::vector<Pel> orgBuf( org_stride * height );
+    std::vector<Pel> curBuf( cur_stride * height );
+
+    DistParam dtParam;
+    dtParam.org.buf = orgBuf.data();
+    dtParam.org.stride = org_stride;
+    dtParam.cur.buf = curBuf.data();
+    dtParam.cur.stride = cur_stride;
+    dtParam.org.width = width;
+    dtParam.org.height = height;
+    dtParam.bitDepth = 10;
+    dtParam.applyWeight = 0; // applyWeight appears to be always zero.
+
+    std::generate( orgBuf.begin(), orgBuf.end(), g10 );
+    std::generate( curBuf.begin(), curBuf.end(), g10 );
+
+    const int index = ( fast ? DF_HAD_fast : DF_HAD ) + log2( width );
+    Distortion sum_ref = ref->m_afpDistortFunc[0][( DFunc )( index )]( dtParam );
+    Distortion sum_opt = opt->m_afpDistortFunc[0][( DFunc )( index )]( dtParam );
+    passed = compare_value( sstm.str(), sum_ref, sum_opt ) && passed;
+  }
+  return passed;
+}
+
 static bool check_SADwMask( RdCost* ref, RdCost* opt, unsigned num_cases, int width, int height )
 {
   std::ostringstream sstm;
@@ -1366,6 +1406,12 @@ static bool test_RdCost()
       passed = check_fixWeightedSSE( &ref, &opt, num_cases, w, h ) && passed;
       passed = check_SAD( &ref, &opt, num_cases, w, h ) && passed;
 
+      if( w >= 2 )
+      {
+        passed = check_HADs( &ref, &opt, num_cases, w, h, /*fast=*/true ) && passed;
+        passed = check_HADs( &ref, &opt, num_cases, w, h, /*fast=*/false ) && passed;
+      }
+
       if (w >= 8 && h >= 8)
       {
         passed = check_SADwMask( &ref, &opt, num_cases, w, h ) && passed;