diff --git a/tests/unit/libutil-support/tests/characterization.hh b/tests/unit/libutil-support/tests/characterization.hh
index db82476da..2bf606bd8 100644
--- a/tests/unit/libutil-support/tests/characterization.hh
+++ b/tests/unit/libutil-support/tests/characterization.hh
@@ -9,17 +9,10 @@
 #include <filesystem>
 
 #include "types.hh"
+#include "test-data.hh"
 
 namespace nix {
 
-/**
- * The path to the unit test data directory. See the contributing guide
- * in the manual for further details.
- */
-static Path getUnitTestData() {
-    return getEnv("_NIX_TEST_UNIT_DATA").value();
-}
-
 /**
  * Whether we should update "golden masters" instead of running tests
  * against them. See the contributing guide in the manual for further
diff --git a/tests/unit/libutil-support/tests/test-data.cc b/tests/unit/libutil-support/tests/test-data.cc
new file mode 100644
index 000000000..016bd5e78
--- /dev/null
+++ b/tests/unit/libutil-support/tests/test-data.cc
@@ -0,0 +1,16 @@
+#include "test-data.hh"
+#include "strings.hh"
+
+namespace nix {
+
+Path getUnitTestData()
+{
+    return getEnv("_NIX_TEST_UNIT_DATA").value();
+}
+
+Path getUnitTestDataPath(std::string_view path)
+{
+    return absPath(getUnitTestData() + "/" + path);
+}
+
+}
diff --git a/tests/unit/libstore-support/tests/test-data.hh b/tests/unit/libutil-support/tests/test-data.hh
similarity index 53%
rename from tests/unit/libstore-support/tests/test-data.hh
rename to tests/unit/libutil-support/tests/test-data.hh
index 1fec6f912..794ec6265 100644
--- a/tests/unit/libstore-support/tests/test-data.hh
+++ b/tests/unit/libutil-support/tests/test-data.hh
@@ -1,25 +1,20 @@
 #pragma once
 
-#include "environment-variables.hh"
 #include "types.hh"
+#include "environment-variables.hh"
+#include "file-system.hh"
 
 namespace nix {
 
-// TODO: These helpers should be available in all unit tests.
-
 /**
  * The path to the unit test data directory. See the contributing guide
  * in the manual for further details.
  */
-static Path getUnitTestData() {
-    return getEnv("_NIX_TEST_UNIT_DATA").value();
-}
+Path getUnitTestData();
 
 /**
  * Resolve a path under the unit test data directory to an absolute path.
  */
-static Path getUnitTestDataPath(std::string_view path) {
-    return absPath(getUnitTestData() + "/" + path);
-}
+Path getUnitTestDataPath(std::string_view path);
 
 }
diff --git a/tests/unit/libutil/config.cc b/tests/unit/libutil/config.cc
index 1629969ba..1600f4ff0 100644
--- a/tests/unit/libutil/config.cc
+++ b/tests/unit/libutil/config.cc
@@ -1,5 +1,9 @@
 #include "config.hh"
 #include "args.hh"
+#include "file-system.hh"
+#include "environment-variables.hh"
+#include "logging.hh"
+#include "tests/test-data.hh"
 
 #include <sstream>
 #include <gtest/gtest.h>
@@ -287,6 +291,35 @@ namespace nix {
         ), Error);
     }
 
+    TEST(Config, includeRelativePath) {
+        Config config;
+        Setting<std::string> setting{&config, "", "puppy", "description"};
+
+        config.applyConfig("include puppy.conf", {
+            .path = getUnitTestDataPath("nix.conf")
+        });
+
+        std::map<std::string, Config::SettingInfo> settings;
+        config.getSettings(settings);
+        ASSERT_FALSE(settings.empty());
+        ASSERT_EQ(settings["puppy"].value, "doggy");
+    }
+
+    TEST(Config, includeTildePath) {
+        Config config;
+        Setting<std::string> setting{&config, "", "puppy", "description"};
+
+        config.applyConfig("include ~/puppy.conf", {
+            .path = "/doesnt-exist",
+            .home = getUnitTestData()
+        });
+
+        std::map<std::string, Config::SettingInfo> settings;
+        config.getSettings(settings);
+        ASSERT_FALSE(settings.empty());
+        ASSERT_EQ(settings["puppy"].value, "doggy");
+    }
+
     TEST(Config, applyConfigInvalidThrows) {
         Config config;
         ASSERT_THROW(config.applyConfig("value == key"), UsageError);
diff --git a/tests/unit/libutil/data/puppy.conf b/tests/unit/libutil/data/puppy.conf
new file mode 100644
index 000000000..805e484ef
--- /dev/null
+++ b/tests/unit/libutil/data/puppy.conf
@@ -0,0 +1 @@
+puppy = doggy
diff --git a/tests/unit/meson.build b/tests/unit/meson.build
index 55c7566bd..8ff0b5ec5 100644
--- a/tests/unit/meson.build
+++ b/tests/unit/meson.build
@@ -19,6 +19,7 @@ libutil_test_support_sources = files(
   'libutil-support/tests/cli-literate-parser.cc',
   'libutil-support/tests/hash.cc',
   'libutil-support/tests/terminal-code-eater.cc',
+  'libutil-support/tests/test-data.cc',
 )
 libutil_test_support = library(
   'lixutil-test-support',
@@ -95,7 +96,6 @@ libstore_test_support_sources = files(
   'libstore-support/tests/derived-path.cc',
   'libstore-support/tests/outputs-spec.cc',
   'libstore-support/tests/path.cc',
-  'libstore-support/tests/test-data.hh',
 )
 
 libstore_test_support = library(