diff --git a/unittest/c-library/CMakeLists.txt b/unittest/c-library/CMakeLists.txt
index f5793a804e..62ec750a3f 100644
--- a/unittest/c-library/CMakeLists.txt
+++ b/unittest/c-library/CMakeLists.txt
@@ -3,6 +3,7 @@
 add_executable(test_library_open test_library_open.cpp test_main.cpp)
 target_link_libraries(test_library_open PRIVATE lammps GTest::GMock)
 add_test(NAME LibraryOpen COMMAND test_library_open)
+set_tests_properties(LibraryOpen PROPERTIES ENVIRONMENT "OMP_NUM_THREADS=4;OMP_PROC_BIND=false")
 
 add_executable(test_library_commands test_library_commands.cpp test_main.cpp)
 target_link_libraries(test_library_commands PRIVATE lammps GTest::GMock)
@@ -16,7 +17,7 @@ add_executable(test_library_properties test_library_properties.cpp test_main.cpp
 target_link_libraries(test_library_properties PRIVATE lammps GTest::GMock)
 target_compile_definitions(test_library_properties PRIVATE -DTEST_INPUT_FOLDER=${CMAKE_CURRENT_SOURCE_DIR})
 add_test(NAME LibraryProperties COMMAND test_library_properties)
-set_tests_properties(LibraryProperties PROPERTIES ENVIRONMENT "LAMMPS_POTENTIALS=${LAMMPS_POTENTIALS_DIR}")
+set_tests_properties(LibraryProperties PROPERTIES ENVIRONMENT "LAMMPS_POTENTIALS=${LAMMPS_POTENTIALS_DIR};OMP_NUM_THREADS=4;OMP_PROC_BIND=false")
 
 add_executable(test_library_objects test_library_objects.cpp test_main.cpp)
 target_link_libraries(test_library_objects PRIVATE lammps GTest::GMock)
diff --git a/unittest/c-library/test_library_open.cpp b/unittest/c-library/test_library_open.cpp
index 426b2adaa7..6f2ea9ac33 100644
--- a/unittest/c-library/test_library_open.cpp
+++ b/unittest/c-library/test_library_open.cpp
@@ -2,10 +2,12 @@
 
 #include "lammps.h"
 #define LAMMPS_LIB_MPI 1
+#include "info.h"
 #include "library.h"
 #include <cstdio> // for stdin, stdout
 #include <mpi.h>
 #include <string>
+#include <vector>
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
@@ -78,9 +80,38 @@ TEST(lammps_open, with_args)
 TEST(lammps_open, with_kokkos)
 {
     if (!LAMMPS_NS::LAMMPS::is_installed_pkg("KOKKOS")) GTEST_SKIP();
-    const char *args[] = {"liblammps", "-k", "on", "t", "2", "-sf", "kk", "-log", "none", nullptr};
-    char **argv        = (char **)args;
-    int argc           = (sizeof(args) / sizeof(char *)) - 1;
+    std::vector<char *> args = {(char *)"lammps", (char *)"-log", (char *)"none", (char *)"-echo",
+                                (char *)"screen", (char *)"-sf",  (char *)"kk"};
+
+    char *one  = (char *)"1";
+    char *four = (char *)"4";
+    char *tee  = (char *)"t";
+    char *gee  = (char *)"g";
+    char *kay  = (char *)"-k";
+    char *yes  = (char *)"on";
+
+    args.push_back(kay);
+    args.push_back(yes);
+
+    // when GPU support is enabled in KOKKOS, it *must* be used
+    if (lammps_config_accelerator("KOKKOS", "api", "hip") ||
+        lammps_config_accelerator("KOKKOS", "api", "cuda") ||
+        lammps_config_accelerator("KOKKOS", "api", "sycl")) {
+        args.push_back(gee);
+        args.push_back(one);
+    }
+
+    // use threads or serial
+    args.push_back(tee);
+    if (lammps_config_accelerator("KOKKOS", "api", "openmp")) {
+        args.push_back(four);
+    } else if (lammps_config_accelerator("KOKKOS", "api", "pthreads")) {
+        args.push_back(four);
+    } else {
+        args.push_back(one);
+    }
+    int argc    = args.size();
+    char **argv = args.data();
 
     ::testing::internal::CaptureStdout();
     void *alt_ptr;
diff --git a/unittest/c-library/test_library_properties.cpp b/unittest/c-library/test_library_properties.cpp
index 3900265f8c..a2df55d120 100644
--- a/unittest/c-library/test_library_properties.cpp
+++ b/unittest/c-library/test_library_properties.cpp
@@ -7,6 +7,7 @@
 #include "lmptype.h"
 #include "platform.h"
 #include <string>
+#include <vector>
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
@@ -742,14 +743,45 @@ TEST_F(AtomProperties, position)
 TEST(SystemSettings, kokkos)
 {
     if (!lammps_config_has_package("KOKKOS")) GTEST_SKIP();
-    if (!lammps_config_accelerator("KOKKOS", "api", "openmp")) GTEST_SKIP();
+    std::vector<char *> args = {(char *)"lammps", (char *)"-log",   (char *)"none",
+                                (char *)"-echo",  (char *)"screen", (char *)"-nocite",
+                                (char *)"-sf",    (char *)"kk"};
 
-    // clang-format off
-    const char *args[] = {"SystemSettings", "-log", "none", "-echo", "screen", "-nocite",
-                          "-k", "on", "t", "4", "-sf", "kk", nullptr};
-    // clang-format on
-    char **argv = (char **)args;
-    int argc    = (sizeof(args) / sizeof(char *)) - 1;
+    char *one  = (char *)"1";
+    char *four = (char *)"4";
+    char *tee  = (char *)"t";
+    char *gee  = (char *)"g";
+    char *kay  = (char *)"-k";
+    char *yes  = (char *)"on";
+
+    args.push_back(kay);
+    args.push_back(yes);
+
+    bool has_gpu     = false;
+    bool has_threads = false;
+
+    // when GPU support is enabled in KOKKOS, it *must* be used
+    if (lammps_config_accelerator("KOKKOS", "api", "hip") ||
+        lammps_config_accelerator("KOKKOS", "api", "cuda") ||
+        lammps_config_accelerator("KOKKOS", "api", "sycl")) {
+        has_gpu = true;
+        args.push_back(gee);
+        args.push_back(one);
+    }
+
+    // use threads or serial
+    args.push_back(tee);
+    if (lammps_config_accelerator("KOKKOS", "api", "openmp")) {
+        has_threads = true;
+        args.push_back(four);
+    } else if (lammps_config_accelerator("KOKKOS", "api", "pthreads")) {
+        has_threads = true;
+        args.push_back(four);
+    } else {
+        args.push_back(one);
+    }
+    int argc    = args.size();
+    char **argv = args.data();
 
     ::testing::internal::CaptureStdout();
     void *lmp          = lammps_open_no_mpi(argc, argv, nullptr);
@@ -758,7 +790,13 @@ TEST(SystemSettings, kokkos)
     EXPECT_THAT(output, StartsWith("LAMMPS ("));
 
     EXPECT_EQ(lammps_extract_setting(lmp, "kokkos_active"), 1);
-    EXPECT_EQ(lammps_extract_setting(lmp, "kokkos_nthreads"), 4);
-    EXPECT_EQ(lammps_extract_setting(lmp, "kokkos_ngpus"), 0);
+    if (has_threads)
+        EXPECT_EQ(lammps_extract_setting(lmp, "kokkos_nthreads"), 4);
+    else
+        EXPECT_EQ(lammps_extract_setting(lmp, "kokkos_nthreads"), 1);
+    if (has_gpu)
+        EXPECT_EQ(lammps_extract_setting(lmp, "kokkos_ngpus"), 1);
+    else
+        EXPECT_EQ(lammps_extract_setting(lmp, "kokkos_ngpus"), 0);
     lammps_close(lmp);
 }
diff --git a/unittest/cplusplus/CMakeLists.txt b/unittest/cplusplus/CMakeLists.txt
index 445e0fffeb..dac4cf3e10 100644
--- a/unittest/cplusplus/CMakeLists.txt
+++ b/unittest/cplusplus/CMakeLists.txt
@@ -3,7 +3,7 @@
 add_executable(test_lammps_class test_lammps_class.cpp)
 target_link_libraries(test_lammps_class PRIVATE lammps GTest::GMockMain)
 add_test(NAME LammpsClass COMMAND test_lammps_class)
-set_tests_properties(LammpsClass PROPERTIES ENVIRONMENT "OMP_NUM_THREADS=1")
+set_tests_properties(LammpsClass PROPERTIES ENVIRONMENT "OMP_NUM_THREADS=2;OMP_PROC_BIND=false")
 
 add_executable(test_input_class test_input_class.cpp)
 target_link_libraries(test_input_class PRIVATE lammps GTest::GTestMain)
diff --git a/unittest/cplusplus/test_lammps_class.cpp b/unittest/cplusplus/test_lammps_class.cpp
index 23d83c4ecb..464ecca925 100644
--- a/unittest/cplusplus/test_lammps_class.cpp
+++ b/unittest/cplusplus/test_lammps_class.cpp
@@ -253,6 +253,15 @@ protected:
     {
         LAMMPS::argv args = {"LAMMPS_test", "-log", "none", "-echo", "none", "-screen", "none",
                              "-k",          "on",   "t",    "1",     "-sf",  "kk"};
+
+        // when GPU support is enabled in KOKKOS, it *must* be used
+        if (Info::has_accelerator_feature("KOKKOS", "api", "hip") ||
+            Info::has_accelerator_feature("KOKKOS", "api", "cuda") ||
+            Info::has_accelerator_feature("KOKKOS", "api", "sycl")) {
+            args = {"LAMMPS_test", "-log", "none", "-echo", "none", "-screen", "none", "-k",
+                    "on",          "t",    "1",    "g",     "1",    "-sf",     "kk"};
+        }
+
         if (Info::has_accelerator_feature("KOKKOS", "api", "openmp")) args[10] = "2";
 
         if (LAMMPS::is_installed_pkg("KOKKOS")) {