diff --git a/cpp/tests/test_defaults.cpp b/cpp/tests/test_defaults.cpp
new file mode 100644
index 0000000000..8c6a91ff89
--- /dev/null
+++ b/cpp/tests/test_defaults.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2024, NVIDIA CORPORATION.
+ *
+ * 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 <stdexcept>
+#include <unordered_map>
+
+#include <gtest/gtest.h>
+#include <kvikio/defaults.hpp>
+
+TEST(Defaults, parse_compat_mode_str)
+{
+  {
+    std::vector<std::string> inputs{"ON", "on", "On"};
+    for (const auto& input : inputs) {
+      EXPECT_EQ(kvikio::detail::parse_compat_mode_str(input), kvikio::detail::CompatMode::ON);
+    }
+  }
+
+  {
+    std::vector<std::string> inputs{"OFF", "off", "oFf"};
+    for (const auto& input : inputs) {
+      EXPECT_EQ(kvikio::detail::parse_compat_mode_str(input), kvikio::detail::CompatMode::OFF);
+    }
+  }
+
+  {
+    std::vector<std::string> inputs{"AUTO", "auto", "aUtO"};
+    for (const auto& input : inputs) {
+      EXPECT_EQ(kvikio::detail::parse_compat_mode_str(input), kvikio::detail::CompatMode::AUTO);
+    }
+  }
+
+  {
+    std::vector<std::string> inputs{"", "invalidOption"};
+    for (const auto& input : inputs) {
+      EXPECT_THROW(kvikio::detail::parse_compat_mode_str(input), std::invalid_argument);
+    }
+  }
+}
\ No newline at end of file