diff --git a/ci/build.sh b/ci/build.sh
index b3b318d093..02f4d4c9dd 100755
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -189,6 +189,7 @@ cmake \
     -DOPENVDB_BUILD_VDB_PRINT=ON \
     -DOPENVDB_BUILD_VDB_LOD=ON \
     -DOPENVDB_BUILD_VDB_TOOL=ON \
+    -DBUILD_TEST=ON \
     -DOPENVDB_TOOL_USE_NANO=OFF \
     -DOPENVDB_BUILD_PYTHON_UNITTESTS=ON \
     -DMSVC_MP_THREAD_COUNT=${PARMS[-j]} \
diff --git a/openvdb_cmd/vdb_tool/CMakeLists.txt b/openvdb_cmd/vdb_tool/CMakeLists.txt
index da1ade24ca..9ed79ff1ea 100644
--- a/openvdb_cmd/vdb_tool/CMakeLists.txt
+++ b/openvdb_cmd/vdb_tool/CMakeLists.txt
@@ -191,4 +191,5 @@ if(BUILD_TEST)
   add_executable(vdb_tool_test src/unittest.cpp)
   target_include_directories(vdb_tool_test PRIVATE vdb_tool_common)
   target_link_libraries(vdb_tool_test PRIVATE vdb_tool_common GTest::gmock GTest::gtest GTest::gmock_main GTest::gtest_main)
+  add_test(vdb_tool_unit_test vdb_tool_test)
 endif()
diff --git a/openvdb_cmd/vdb_tool/include/Geometry.h b/openvdb_cmd/vdb_tool/include/Geometry.h
index 8ce2d4f9b0..620aeac3ef 100644
--- a/openvdb_cmd/vdb_tool/include/Geometry.h
+++ b/openvdb_cmd/vdb_tool/include/Geometry.h
@@ -33,7 +33,7 @@
 
 #ifdef VDB_TOOL_USE_NANO
 #include <nanovdb/NanoVDB.h>
-#include <nanovdb/util/IO.h>
+#include <nanovdb/io/IO.h>
 #endif
 
 #ifdef VDB_TOOL_USE_ABC
diff --git a/openvdb_cmd/vdb_tool/include/Tool.h b/openvdb_cmd/vdb_tool/include/Tool.h
index 24e947f79b..b24e71696e 100644
--- a/openvdb_cmd/vdb_tool/include/Tool.h
+++ b/openvdb_cmd/vdb_tool/include/Tool.h
@@ -53,9 +53,9 @@
 
 #ifdef VDB_TOOL_USE_NANO
 #include <nanovdb/NanoVDB.h>
-#include <nanovdb/util/IO.h>
-#include <nanovdb/util/CreateNanoGrid.h>
-#include <nanovdb/util/NanoToOpenVDB.h>
+#include <nanovdb/io/IO.h>
+#include <nanovdb/tools/CreateNanoGrid.h>
+#include <nanovdb/tools/NanoToOpenVDB.h>
 #endif
 
 #ifdef VDB_TOOL_USE_EXR
@@ -1062,7 +1062,7 @@ void Tool::readNVDB(const std::string &fileName)
   const size_t count = mGrid.size();
   if (grids.size()) {
     for (const auto& gridHandle : grids) {
-      if (gridNames[0]=="*" || findMatch(gridHandle.gridMetaData()->shortGridName(), gridNames)) mGrid.push_back(nanovdb::nanoToOpenVDB(gridHandle));
+      if (gridNames[0]=="*" || findMatch(gridHandle.gridMetaData()->shortGridName(), gridNames)) mGrid.push_back(nanovdb::tools::nanoToOpenVDB(gridHandle));
     }
   } else if (mParser.verbose>0) {
     std::cerr << "readVDB: no vdb grids in \"" << fileName << "\"";
@@ -1262,26 +1262,26 @@ void Tool::writeNVDB(const std::string &fileName)
       throw std::invalid_argument("writeNVDB: unsupported bits \""+bits+"\"");
     }
 
-    nanovdb::StatsMode sMode = nanovdb::StatsMode::Default;
+    nanovdb::tools::StatsMode sMode = nanovdb::tools::StatsMode::Default;
     if (stats == "none") {
-      sMode = nanovdb::StatsMode::Disable;
+      sMode = nanovdb::tools::StatsMode::Disable;
     } else if (stats == "bbox") {
-      sMode = nanovdb::StatsMode::BBox;
+      sMode = nanovdb::tools::StatsMode::BBox;
     } else if (stats == "extrema") {
-      sMode = nanovdb::StatsMode::MinMax;
+      sMode = nanovdb::tools::StatsMode::MinMax;
     } else if (stats == "all") {
-      sMode = nanovdb::StatsMode::All;
+      sMode = nanovdb::tools::StatsMode::All;
     } else if (stats != "") {
       throw std::invalid_argument("writeNVDB: unsupported stats \""+stats+"\"");
     }
 
-    nanovdb::ChecksumMode cMode = nanovdb::ChecksumMode::Default;
+    nanovdb::CheckMode cMode = nanovdb::CheckMode::Default;
     if (checksum == "none") {
-      cMode = nanovdb::ChecksumMode::Disable;
+      cMode = nanovdb::CheckMode::Disable;
     } else if (checksum == "partial") {
-      cMode = nanovdb::ChecksumMode::Partial;
+      cMode = nanovdb::CheckMode::Partial;
     } else if (checksum == "full") {
-      cMode = nanovdb::ChecksumMode::Full;
+      cMode = nanovdb::CheckMode::Full;
     } else if (checksum != "") {
       throw std::invalid_argument("writeNVDB: unsupported checksum \""+checksum+"\"");
     }
@@ -1302,21 +1302,21 @@ void Tool::writeNVDB(const std::string &fileName)
         using SrcGridT = openvdb::FloatGrid;
         switch (qMode){
         case nanovdb::GridType::Fp4:
-          return nanovdb::createNanoGrid<SrcGridT, nanovdb::Fp4>(*floatGrid, sMode, cMode, dither, verbose);
+          return nanovdb::tools::createNanoGrid<SrcGridT, nanovdb::Fp4>(*floatGrid, sMode, cMode, dither, verbose);
         case nanovdb::GridType::Fp8:
-          return nanovdb::createNanoGrid<SrcGridT, nanovdb::Fp8>(*floatGrid, sMode, cMode, dither, verbose);
+          return nanovdb::tools::createNanoGrid<SrcGridT, nanovdb::Fp8>(*floatGrid, sMode, cMode, dither, verbose);
         case nanovdb::GridType::Fp16:
-          return nanovdb::createNanoGrid<SrcGridT, nanovdb::Fp16>(*floatGrid, sMode, cMode, dither, verbose);
+          return nanovdb::tools::createNanoGrid<SrcGridT, nanovdb::Fp16>(*floatGrid, sMode, cMode, dither, verbose);
         case nanovdb::GridType::FpN:
           if (absolute) {
-            return nanovdb::createNanoGrid<SrcGridT, nanovdb::FpN>(*floatGrid, sMode, cMode, dither, verbose, nanovdb::AbsDiff(tolerance));
+            return nanovdb::tools::createNanoGrid<SrcGridT, nanovdb::FpN>(*floatGrid, sMode, cMode, dither, verbose, nanovdb::tools::AbsDiff(tolerance));
           } else {
-            return nanovdb::createNanoGrid<SrcGridT, nanovdb::FpN>(*floatGrid, sMode, cMode, dither, verbose, nanovdb::RelDiff(tolerance));
+            return nanovdb::tools::createNanoGrid<SrcGridT, nanovdb::FpN>(*floatGrid, sMode, cMode, dither, verbose, nanovdb::tools::RelDiff(tolerance));
           }
         default: break;// 32 bit float grids are handled below
         }// end of switch
       }
-      return nanovdb::openToNanoVDB(base, sMode, cMode, verbose);// float and other grids
+      return nanovdb::tools::openToNanoVDB(base, sMode, cMode, verbose);// float and other grids
     };// openToNano
 
     if (fileName=="stdout.nvdb") {
diff --git a/openvdb_cmd/vdb_tool/src/unittest.cpp b/openvdb_cmd/vdb_tool/src/unittest.cpp
index 0510e17412..9ca0f9cbca 100644
--- a/openvdb_cmd/vdb_tool/src/unittest.cpp
+++ b/openvdb_cmd/vdb_tool/src/unittest.cpp
@@ -411,7 +411,7 @@ TEST_F(Test_vdb_tool, Geometry)
   {// test readOFF and writeOFF
     geo.write("data/test.off");
     openvdb::vdb_tool::Geometry geo2;
-    EXPECT_TRUE(geo2.read("data/test.off"));
+    geo2.read("data/test.off");
     EXPECT_EQ(4, geo2.vtxCount());
     EXPECT_EQ(2, geo2.triCount());
     EXPECT_EQ(1, geo2.quadCount());
@@ -820,7 +820,7 @@ TEST_F(Test_vdb_tool, ToolParser)
     float beta = 0.0f, beta_sum = 0.0f;
     std::string path, base, ext;
 
-    Parser p({{"alpha", "64"}, {"beta", "4.56"}});
+    Parser p({{"alpha", "64", "", ""}, {"beta", "4.56", "", ""}});
     p.addAction("process_a", "a", "docs",
               {{"alpha", "", "", ""},{"beta", "", "", ""}},
                [&](){p.setDefaults();},
@@ -843,7 +843,7 @@ TEST_F(Test_vdb_tool, ToolParser)
     p.finalize();
 
     auto args = getArgs("vdb_tool -quiet -process_a alpha=128 -for v=0.1,0.4,0.1 -b alpha={$#v:++} beta={$v} -end");
-    p.parse(args.size(), args.data());
+    p.parse(int(args.size()), args.data());
     EXPECT_EQ(0, alpha);
     EXPECT_EQ(0.0f, beta);
     EXPECT_EQ(0, alpha_sum);
@@ -855,7 +855,7 @@ TEST_F(Test_vdb_tool, ToolParser)
     EXPECT_EQ(0.1f + 0.2f + 0.3f, beta_sum);// derived from loop
 
     args = getArgs("vdb_tool -quiet -each file=path1/base1.ext1,path2/base2.ext2 -c alpha={$file:path} beta={$file:name} gamma={$file:ext} -end");
-    p.parse(args.size(), args.data());
+    p.parse(int(args.size()), args.data());
     p.run();
     EXPECT_EQ(path, "path1,path2");
     EXPECT_EQ(base, "base1,base2");
@@ -875,7 +875,7 @@ TEST_F(Test_vdb_tool, ToolBasic)
 
     EXPECT_NO_THROW({
       auto args = getArgs("vdb_tool -quiet -sphere r=1.1 -ls2mesh -write data/sphere.ply data/config.txt");
-      Tool vdb_tool(args.size(), args.data());
+      Tool vdb_tool(int(args.size()), args.data());
       vdb_tool.run();
     });
 
@@ -896,7 +896,7 @@ TEST_F(Test_vdb_tool, Counter)
 
     EXPECT_NO_THROW({
       auto args = getArgs("vdb_tool -quiet -eval {1:@G} -sphere r=1.1 -ls2mesh -write data/sphere_{$G}.ply data/config_{$G:++}.txt");
-      Tool vdb_tool(args.size(), args.data());
+      Tool vdb_tool(int(args.size()), args.data());
       vdb_tool.run();
     });
 
@@ -919,7 +919,7 @@ TEST_F(Test_vdb_tool, ToolForLoop)
     // test single for-loop
     EXPECT_NO_THROW({
       auto args = getArgs("vdb_tool -quiet -for i=0,3 -sphere r=1.{$i} dim=128 name=sphere_{$i} -ls2mesh -write data/sphere_{$#i:++}.ply -end");
-      Tool vdb_tool(args.size(), args.data());
+      Tool vdb_tool(int(args.size()), args.data());
       vdb_tool.run();
     });
 
@@ -928,7 +928,7 @@ TEST_F(Test_vdb_tool, ToolForLoop)
     // test two nested for-loops
     EXPECT_NO_THROW({
       auto args = getArgs("vdb_tool -quiet -for v=0.1,0.3,0.1 -each s=sphere_1,sphere_3 -read ./data/{$s}.ply -mesh2ls voxel={$v} -end -end -write data/test.vdb");
-      Tool vdb_tool(args.size(), args.data());
+      Tool vdb_tool(int(args.size()), args.data());
       vdb_tool.run();
     });
 
@@ -948,7 +948,7 @@ TEST_F(Test_vdb_tool, ToolError)
 
     EXPECT_THROW({
       auto args = getArgs("vdb_tool -sphere bla=3 -ls2mesh -write data/sphere.ply data/config.txt -quiet");
-      Tool vdb_tool(args.size(), args.data());
+      Tool vdb_tool(int(args.size()), args.data());
       vdb_tool.run();
     }, std::invalid_argument);
 
@@ -971,7 +971,7 @@ TEST_F(Test_vdb_tool, ToolKeep)
 
     EXPECT_NO_THROW({
       auto args = getArgs("vdb_tool -quiet -default keep=1 -sphere r=2 -ls2mesh vdb=0 -write vdb=0 geo=0 data/sphere.vdb data/sphere.ply data/config.txt");
-      Tool vdb_tool(args.size(), args.data());
+      Tool vdb_tool(int(args.size()), args.data());
       vdb_tool.run();
     });
 
@@ -994,7 +994,7 @@ TEST_F(Test_vdb_tool, ToolConfig)
 
     EXPECT_NO_THROW({
       auto args = getArgs("vdb_tool -quiet -config data/config.txt");
-      Tool vdb_tool(args.size(), args.data());
+      Tool vdb_tool(int(args.size()), args.data());
       vdb_tool.run();
     });