diff --git a/tests/unit/libutil/nix_api_util.cc b/tests/unit/libutil/nix_api_util.cc
new file mode 100644
index 000000000..26353fe84
--- /dev/null
+++ b/tests/unit/libutil/nix_api_util.cc
@@ -0,0 +1,125 @@
+
+#include "config.hh"
+#include "args.hh"
+#include "nix_api_util.h"
+#include "nix_api_util_internal.h"
+
+#include <gtest/gtest.h>
+
+namespace nixC {
+
+class nix_api_util_context : public ::testing::Test {
+protected:
+    static void SetUpTestSuite() {
+        nix_libutil_init(NULL);
+    }
+    void SetUp() override {
+        ctx = nix_c_context_create();
+    };
+    void TearDown() override {
+        nix_c_context_free(ctx);
+        ctx = nullptr;
+    }
+    nix_c_context* ctx;
+};
+
+TEST_F(nix_api_util_context, nix_context_error) {
+    std::string err_msg_ref;
+    try {
+        throw nix::Error("testing error");
+    } catch(nix::Error &e) {
+        err_msg_ref = e.what();
+        nix_context_error(ctx);
+    }
+    ASSERT_EQ(ctx->last_err_code, NIX_ERR_NIX_ERROR);
+    ASSERT_EQ(ctx->name, "nix::Error");
+    ASSERT_EQ(*ctx->last_err, err_msg_ref);
+    ASSERT_EQ(ctx->info->msg.str(), "testing error");
+
+    try {
+        throw std::runtime_error("testing exception");
+    } catch(std::exception &e) {
+        err_msg_ref = e.what();
+        nix_context_error(ctx);
+    }
+    ASSERT_EQ(ctx->last_err_code, NIX_ERR_UNKNOWN);
+    ASSERT_EQ(*ctx->last_err, err_msg_ref);
+}
+
+TEST_F(nix_api_util_context, nix_set_err_msg) {
+    ASSERT_EQ(ctx->last_err_code, NIX_OK);
+    nix_set_err_msg(ctx, NIX_ERR_UNKNOWN, "unknown test error");
+    ASSERT_EQ(ctx->last_err_code, NIX_ERR_UNKNOWN);
+    ASSERT_EQ(*ctx->last_err, "unknown test error");
+}
+
+TEST(nix_api_util, nix_version_get) {
+    ASSERT_EQ(std::string(nix_version_get()), PACKAGE_VERSION);
+}
+
+TEST_F(nix_api_util_context, nix_setting_get) {
+    // todo
+}
+
+TEST_F(nix_api_util_context, nix_setting_set) {
+    // todo
+}
+
+TEST_F(nix_api_util_context, nix_err_msg) {
+    // no error
+    EXPECT_THROW(nix_err_msg(NULL, ctx, NULL), nix::Error);
+
+    // set error
+    nix_set_err_msg(ctx, NIX_ERR_UNKNOWN, "unknown test error");
+
+    // basic usage
+    std::string err_msg = nix_err_msg(NULL, ctx, NULL);
+    ASSERT_EQ(err_msg, "unknown test error");
+
+    // advanced usage
+    unsigned int sz;
+    err_msg = nix_err_msg(NULL, ctx, &sz);
+    ASSERT_EQ(sz, err_msg.size());
+}
+
+TEST_F(nix_api_util_context, nix_err_info_msg) {
+    // no error
+    EXPECT_THROW(nix_err_info_msg(NULL, ctx, NULL, 256), nix::Error);
+
+    try {
+        throw nix::Error("testing error");
+    } catch(...) {
+        nix_context_error(ctx);
+    }
+    char buf[256];
+    nix_err_info_msg(NULL, ctx, buf, 256);
+    ASSERT_EQ(std::string(buf), "testing error");
+
+    // should overflow
+    EXPECT_THROW(nix_err_info_msg(NULL, ctx, buf, 1), nix::Error);
+}
+
+TEST_F(nix_api_util_context, nix_err_name) {
+    // no error
+    EXPECT_THROW(nix_err_name(NULL, ctx, NULL, 256), nix::Error);
+
+    std::string err_msg_ref;
+    try {
+        throw nix::Error("testing error");
+    } catch(...) {
+        nix_context_error(ctx);
+    }
+    char err_name[32];
+    nix_err_name(NULL, ctx, err_name, 32);
+    ASSERT_EQ(std::string(err_name), "nix::Error");
+
+    // overflow
+    EXPECT_THROW(nix_err_name(NULL, ctx, err_name, 1), nix::Error);
+}
+
+TEST_F(nix_api_util_context, nix_err_code) {
+    ASSERT_EQ(nix_err_code(ctx), NIX_OK);
+    nix_set_err_msg(ctx, NIX_ERR_UNKNOWN, "unknown test error");
+    ASSERT_EQ(nix_err_code(ctx), NIX_ERR_UNKNOWN);
+}
+}