diff --git a/tests/unit/libexpr/local.mk b/tests/unit/libexpr/local.mk
index eda65508d..0a7b28436 100644
--- a/tests/unit/libexpr/local.mk
+++ b/tests/unit/libexpr/local.mk
@@ -32,6 +32,6 @@ libexpr-tests_CXXFLAGS += $(libexpr-tests_EXTRA_INCLUDES)
 
 libexpr-tests_LIBS = \
     libexpr-test-support libstore-test-support libutils-test-support \
-    libexpr libfetchers libstore libutil
+    libexpr libexprc libfetchers libstore libstorec libutil libutilc
 
 libexpr-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS) -lgmock
diff --git a/tests/unit/libexpr/nix_api_expr.cc b/tests/unit/libexpr/nix_api_expr.cc
new file mode 100644
index 000000000..03de4547a
--- /dev/null
+++ b/tests/unit/libexpr/nix_api_expr.cc
@@ -0,0 +1,82 @@
+#include "nix_api_store.h"
+#include "nix_api_store_internal.h"
+#include "nix_api_util.h"
+#include "nix_api_util_internal.h"
+#include "nix_api_expr.h"
+#include "nix_api_value.h"
+
+#include "tests/nix_api_store.hh"
+
+#include <gtest/gtest.h>
+
+namespace nixC {
+
+class nix_api_expr_test : public nix_api_store_test
+{
+public:
+    nix_api_expr_test()
+    {
+        state = nix_state_create(nullptr, nullptr, store);
+        value = nix_alloc_value(nullptr, state);
+    }
+    ~nix_api_expr_test()
+    {
+        nix_gc_decref(nullptr, value);
+        nix_state_free(state);
+    }
+
+    State * state;
+    Value * value;
+};
+
+TEST_F(nix_api_expr_test, nix_expr_eval_from_string)
+{
+    nix_expr_eval_from_string(nullptr, state, "builtins.nixVersion", ".", value);
+    nix_value_force(nullptr, state, value);
+    auto result = nix_get_string(nullptr, value);
+
+    ASSERT_STREQ(PACKAGE_VERSION, result);
+}
+
+TEST_F(nix_api_expr_test, nix_expr_eval_add_numbers)
+{
+    nix_expr_eval_from_string(nullptr, state, "1 + 1", ".", value);
+    nix_value_force(nullptr, state, value);
+    auto result = nix_get_int(nullptr, value);
+
+    ASSERT_EQ(2, result);
+}
+
+TEST_F(nix_api_expr_test, nix_expr_eval_drv)
+{
+    auto expr = R"(derivation { name = "myname"; builder = "mybuilder"; system = "mysystem"; })";
+    nix_expr_eval_from_string(nullptr, state, expr, ".", value);
+    nix_value_force(nullptr, state, value);
+
+    ASSERT_EQ(NIX_TYPE_ATTRS, nix_get_type(nullptr, value));
+
+    auto stateFn = nix_state_create(nullptr, nullptr, store);
+    auto valueFn = nix_alloc_value(nullptr, state);
+    nix_expr_eval_from_string(nullptr, stateFn, "builtins.toString", ".", valueFn);
+
+    ASSERT_EQ(NIX_TYPE_FUNCTION, nix_get_type(nullptr, valueFn));
+
+    auto stateResult = nix_state_create(nullptr, nullptr, store);
+    auto valueResult = nix_alloc_value(nullptr, stateResult);
+
+    nix_value_call(ctx, stateResult, valueFn, value, valueResult);
+    nix_value_force(nullptr, stateResult, valueResult);
+
+    auto p = nix_get_string(nullptr, valueResult);
+
+    ASSERT_STREQ("/nix/store/40s0qmrfb45vlh6610rk29ym318dswdr-myname", p);
+
+    // Clean up
+    nix_gc_decref(nullptr, valueFn);
+    nix_state_free(stateFn);
+
+    nix_gc_decref(nullptr, valueResult);
+    nix_state_free(stateResult);
+}
+
+}
diff --git a/tests/unit/libstore-support/tests/nix_api_store.hh b/tests/unit/libstore-support/tests/nix_api_store.hh
new file mode 100644
index 000000000..e762a3ca8
--- /dev/null
+++ b/tests/unit/libstore-support/tests/nix_api_store.hh
@@ -0,0 +1,40 @@
+#pragma once
+///@file
+#include "tests/nix_api_util.hh"
+
+#include "nix_api_store.h"
+#include "nix_api_store_internal.h"
+
+#include <filesystem>
+#include <gtest/gtest.h>
+
+namespace fs = std::filesystem;
+
+class nix_api_store_test : public nix_api_util_context
+{
+public:
+    nix_api_store_test()
+    {
+        nix_libstore_init(ctx);
+
+        auto tmpl = nix::getEnv("TMPDIR").value_or("/tmp") + "/tests_nix-store.XXXXXX";
+        nixStoreDir = mkdtemp((char *) tmpl.c_str());
+
+        // Options documented in `nix help-stores`
+        const char * p1[] = {"root", nixStoreDir.c_str()};
+        const char ** params[] = {p1, nullptr};
+        store = nix_store_open(ctx, "local", params);
+    };
+    ~nix_api_store_test() override
+    {
+        nix_store_unref(store);
+
+        for (auto & path : fs::recursive_directory_iterator(nixStoreDir)) {
+            fs::permissions(path, fs::perms::owner_all);
+        }
+        fs::remove_all(nixStoreDir);
+    }
+
+    Store * store;
+    std::string nixStoreDir;
+};
diff --git a/tests/unit/libstore/nix_api_store.cc b/tests/unit/libstore/nix_api_store.cc
index 3fe55ae93..764cd0d88 100644
--- a/tests/unit/libstore/nix_api_store.cc
+++ b/tests/unit/libstore/nix_api_store.cc
@@ -2,7 +2,8 @@
 #include "nix_api_util_internal.h"
 #include "nix_api_store.h"
 #include "nix_api_store_internal.h"
-#include "tests/nix_api_util.hh"
+
+#include "tests/nix_api_store.hh"
 
 #define STORE_DIR "/nix/store/"
 #define HASH_PART "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q"
@@ -10,24 +11,6 @@ const char * validPath = STORE_DIR HASH_PART "-x";
 
 namespace nixC {
 
-class nix_api_store_test : public nix_api_util_context
-{
-public:
-    void SetUp() override
-    {
-        nix_api_util_context::SetUp();
-        nix_libstore_init(ctx);
-        store = nix_store_open(ctx, "dummy://", NULL);
-    };
-    void TearDown() override
-    {
-        nix_store_unref(store);
-        nix_api_util_context::TearDown();
-    }
-
-    Store * store;
-};
-
 TEST_F(nix_api_util_context, nix_libstore_init)
 {
     auto ret = nix_libstore_init(ctx);
@@ -39,7 +22,7 @@ TEST_F(nix_api_store_test, nix_store_get_uri)
     char value[256];
     auto ret = nix_store_get_uri(ctx, store, value, 256);
     ASSERT_EQ(NIX_OK, ret);
-    ASSERT_STREQ("dummy", value);
+    ASSERT_STREQ("local", value);
 }
 
 TEST_F(nix_api_store_test, InvalidPathFails)
@@ -67,4 +50,12 @@ TEST_F(nix_api_store_test, DoesNotCrashWhenContextIsNull)
     ASSERT_NO_THROW(nix_store_parse_path(nullptr, store, validPath));
 }
 
+TEST_F(nix_api_store_test, get_version)
+{
+    char value[256];
+    auto ret = nix_store_get_version(ctx, store, value, 256);
+    ASSERT_EQ(NIX_OK, ret);
+    ASSERT_STREQ(PACKAGE_VERSION, value);
+}
+
 }
diff --git a/tests/unit/libutil-support/tests/nix_api_util.hh b/tests/unit/libutil-support/tests/nix_api_util.hh
index f2ee58da2..b007ac4b1 100644
--- a/tests/unit/libutil-support/tests/nix_api_util.hh
+++ b/tests/unit/libutil-support/tests/nix_api_util.hh
@@ -4,7 +4,6 @@
 
 #include <gtest/gtest.h>
 
-
 class nix_api_util_context : public ::testing::Test
 {
 protected:
@@ -12,14 +11,17 @@ protected:
     {
         nix_libutil_init(NULL);
     }
-    void SetUp() override
+
+    nix_api_util_context()
     {
         ctx = nix_c_context_create();
     };
-    void TearDown() override
+
+    ~nix_api_util_context() override
     {
         nix_c_context_free(ctx);
         ctx = nullptr;
     }
+
     nix_c_context * ctx;
 };