diff --git a/lib/filterx/tests/Makefile.am b/lib/filterx/tests/Makefile.am
index 38196a6503b..c6b56569d30 100644
--- a/lib/filterx/tests/Makefile.am
+++ b/lib/filterx/tests/Makefile.am
@@ -18,8 +18,7 @@ lib_filterx_tests_TESTS		 =              \
 		lib/filterx/tests/test_type_registry \
 		lib/filterx/tests/test_filterx_object
 
-EXTRA_DIST += lib/filterx/tests/CMakeLists.txt \
-	lib/filterx/tests/filterx-lib.h
+EXTRA_DIST += lib/filterx/tests/CMakeLists.txt
 
 check_PROGRAMS				+= ${lib_filterx_tests_TESTS}
 
diff --git a/lib/filterx/tests/filterx-lib.h b/lib/filterx/tests/filterx-lib.h
deleted file mode 100644
index 04ac879a008..00000000000
--- a/lib/filterx/tests/filterx-lib.h
+++ /dev/null
@@ -1,37 +0,0 @@
-/*
- * Copyright (c) 2023 Balazs Scheidler <balazs.scheidler@axoflow.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- *
- * As an additional exemption you are allowed to compile & link against the
- * OpenSSL libraries as published by the OpenSSL project. See the file
- * COPYING for details.
- *
- */
-
-static void
-assert_marshaled_object(FilterXObject *obj, const gchar *repr, LogMessageValueType type)
-{
-  GString *b = g_string_sized_new(0);
-  LogMessageValueType t;
-
-  /* check if we _overwrite_ the string with the marshalled value */
-  g_string_append(b, "PREFIX");
-
-  cr_assert(filterx_object_marshal(obj, b, &t) == TRUE);
-  cr_assert_str_eq(b->str, repr);
-  cr_assert_eq(t, type);
-  g_string_free(b, TRUE);
-}
diff --git a/lib/filterx/tests/test_filterx_expr.c b/lib/filterx/tests/test_filterx_expr.c
index 925adba3ec4..6f518e69c7a 100644
--- a/lib/filterx/tests/test_filterx_expr.c
+++ b/lib/filterx/tests/test_filterx_expr.c
@@ -39,7 +39,7 @@
 #include "apphook.h"
 #include "scratch-buffers.h"
 
-#include "filterx-lib.h"
+#include "libtest/filterx-lib.h"
 
 static void
 _assert_int_value_and_unref(FilterXObject *object, gint64 expected_value)
@@ -379,18 +379,6 @@ Test(filterx_expr, test_filterx_assign)
   filterx_eval_set_context(NULL);
 }
 
-static void
-assert_object_json_equals(FilterXObject *obj, const gchar *expected_json_repr)
-{
-  struct json_object *jso = NULL;
-
-  cr_assert(filterx_object_map_to_json(obj, &jso) == TRUE, "error mapping to json, expected json was: %s",
-            expected_json_repr);
-  const gchar *json_repr = json_object_to_json_string_ext(jso, JSON_C_TO_STRING_PLAIN);
-  cr_assert_str_eq(json_repr, expected_json_repr);
-  json_object_put(jso);
-}
-
 Test(filterx_expr, test_filterx_setattr)
 {
   LogMessage *msg = create_sample_message();
diff --git a/lib/filterx/tests/test_object_boolean.c b/lib/filterx/tests/test_object_boolean.c
index f10f834a4d8..a4423651028 100644
--- a/lib/filterx/tests/test_object_boolean.c
+++ b/lib/filterx/tests/test_object_boolean.c
@@ -21,6 +21,8 @@
  *
  */
 #include <criterion/criterion.h>
+#include "libtest/filterx-lib.h"
+
 #include "filterx/object-string.h"
 #include "filterx/object-null.h"
 #include "filterx/object-primitive.h"
diff --git a/lib/filterx/tests/test_object_datetime.c b/lib/filterx/tests/test_object_datetime.c
index 3ab05a420da..391f88cf9fa 100644
--- a/lib/filterx/tests/test_object_datetime.c
+++ b/lib/filterx/tests/test_object_datetime.c
@@ -21,27 +21,17 @@
  *
  */
 #include <criterion/criterion.h>
+#include "libtest/filterx-lib.h"
+
 #include "filterx/object-datetime.h"
 #include "filterx/object-primitive.h"
 #include "filterx/object-null.h"
 #include "filterx/object-string.h"
 #include "apphook.h"
-#include "filterx-lib.h"
 #include "scratch-buffers.h"
 #include "filterx/expr-literal.h"
 #include "filterx/expr-function.h"
 
-static void
-assert_object_json_equals(FilterXObject *obj, const gchar *expected_json_repr)
-{
-  struct json_object *jso = NULL;
-
-  cr_assert(filterx_object_map_to_json(obj, &jso) == TRUE, "error mapping to json, expected json was: %s",
-            expected_json_repr);
-  const gchar *json_repr = json_object_to_json_string_ext(jso, JSON_C_TO_STRING_PLAIN);
-  cr_assert_str_eq(json_repr, expected_json_repr);
-  json_object_put(jso);
-}
 
 Test(filterx_datetime, test_filterx_object_datetime_marshals_to_the_stored_values)
 {
diff --git a/lib/filterx/tests/test_object_double.c b/lib/filterx/tests/test_object_double.c
index 67c396508b5..e5ad6f23a59 100644
--- a/lib/filterx/tests/test_object_double.c
+++ b/lib/filterx/tests/test_object_double.c
@@ -21,10 +21,11 @@
  *
  */
 #include <criterion/criterion.h>
+#include "libtest/filterx-lib.h"
+
 #include "filterx/object-string.h"
 #include "filterx/object-null.h"
 #include "filterx/object-primitive.h"
-
 #include "apphook.h"
 #include "scratch-buffers.h"
 
diff --git a/lib/filterx/tests/test_object_integer.c b/lib/filterx/tests/test_object_integer.c
index 73237f84e31..bb9d6066e92 100644
--- a/lib/filterx/tests/test_object_integer.c
+++ b/lib/filterx/tests/test_object_integer.c
@@ -21,6 +21,8 @@
  *
  */
 #include <criterion/criterion.h>
+#include "libtest/filterx-lib.h"
+
 #include "filterx/object-string.h"
 #include "filterx/object-null.h"
 #include "filterx/object-primitive.h"
diff --git a/lib/filterx/tests/test_object_json.c b/lib/filterx/tests/test_object_json.c
index a7aa11a6447..12bf69643df 100644
--- a/lib/filterx/tests/test_object_json.c
+++ b/lib/filterx/tests/test_object_json.c
@@ -21,24 +21,13 @@
  *
  */
 #include <criterion/criterion.h>
+#include "libtest/filterx-lib.h"
+
 #include "filterx/object-json.h"
 #include "filterx/object-string.h"
 #include "filterx/object-message-value.h"
 #include "filterx/expr-function.h"
 #include "apphook.h"
-#include "filterx-lib.h"
-
-static void
-assert_object_json_equals(FilterXObject *obj, const gchar *expected_json_repr)
-{
-  struct json_object *jso = NULL;
-
-  cr_assert(filterx_object_map_to_json(obj, &jso) == TRUE, "error mapping to json, expected json was: %s",
-            expected_json_repr);
-  const gchar *json_repr = json_object_to_json_string_ext(jso, JSON_C_TO_STRING_PLAIN);
-  cr_assert_str_eq(json_repr, expected_json_repr);
-  json_object_put(jso);
-}
 
 Test(filterx_json, test_filterx_object_json_from_repr)
 {
diff --git a/lib/filterx/tests/test_object_message.c b/lib/filterx/tests/test_object_message.c
index fad0da89d7c..946d600c395 100644
--- a/lib/filterx/tests/test_object_message.c
+++ b/lib/filterx/tests/test_object_message.c
@@ -21,23 +21,12 @@
  *
  */
 #include <criterion/criterion.h>
+#include "libtest/filterx-lib.h"
+
 #include "filterx/object-message-value.h"
 #include "apphook.h"
-#include "filterx-lib.h"
 #include "scratch-buffers.h"
 
-static void
-assert_object_json_equals(FilterXObject *obj, const gchar *expected_json_repr)
-{
-  struct json_object *jso = NULL;
-
-  cr_assert(filterx_object_map_to_json(obj, &jso) == TRUE, "error mapping to json, expected json was: %s",
-            expected_json_repr);
-  const gchar *json_repr = json_object_to_json_string_ext(jso, JSON_C_TO_STRING_PLAIN);
-  cr_assert_str_eq(json_repr, expected_json_repr);
-  json_object_put(jso);
-}
-
 Test(filterx_message, test_filterx_object_message_marshals_to_the_stored_values)
 {
   FilterXObject *fobj = filterx_message_value_new("True", 4, LM_VT_BOOLEAN);
diff --git a/lib/filterx/tests/test_object_null.c b/lib/filterx/tests/test_object_null.c
index f020861765c..0f17d5b3061 100644
--- a/lib/filterx/tests/test_object_null.c
+++ b/lib/filterx/tests/test_object_null.c
@@ -21,23 +21,12 @@
  *
  */
 #include <criterion/criterion.h>
+#include "libtest/filterx-lib.h"
+
 #include "filterx/object-null.h"
 #include "apphook.h"
-#include "filterx-lib.h"
 #include "scratch-buffers.h"
 
-static void
-assert_object_json_equals(FilterXObject *obj, const gchar *expected_json_repr)
-{
-  struct json_object *jso = NULL;
-
-  cr_assert(filterx_object_map_to_json(obj, &jso) == TRUE, "error mapping to json, expected json was: %s",
-            expected_json_repr);
-  const gchar *json_repr = json_object_to_json_string_ext(jso, JSON_C_TO_STRING_PLAIN);
-  cr_assert_str_eq(json_repr, expected_json_repr);
-  json_object_put(jso);
-}
-
 Test(filterx_null, test_filterx_object_null_marshals_to_the_stored_values)
 {
   FilterXObject *fobj = filterx_null_new();
diff --git a/lib/filterx/tests/test_object_primitive.c b/lib/filterx/tests/test_object_primitive.c
index 33ee98f2951..768749763d7 100644
--- a/lib/filterx/tests/test_object_primitive.c
+++ b/lib/filterx/tests/test_object_primitive.c
@@ -21,23 +21,12 @@
  *
  */
 #include <criterion/criterion.h>
+#include "libtest/filterx-lib.h"
+
 #include "filterx/filterx-object.h"
 #include "filterx/object-primitive.h"
 #include "filterx/object-message-value.h"
 #include "apphook.h"
-#include "filterx-lib.h"
-
-static void
-assert_object_json_equals(FilterXObject *obj, const gchar *expected_json_repr)
-{
-  struct json_object *jso = NULL;
-
-  cr_assert(filterx_object_map_to_json(obj, &jso) == TRUE, "error mapping to json, expected json was: %s",
-            expected_json_repr);
-  const gchar *json_repr = json_object_to_json_string_ext(jso, JSON_C_TO_STRING_PLAIN);
-  cr_assert_str_eq(json_repr, expected_json_repr);
-  json_object_put(jso);
-}
 
 Test(filterx_object, test_filterx_object_construction_and_free)
 {
diff --git a/lib/filterx/tests/test_object_string.c b/lib/filterx/tests/test_object_string.c
index 66c9739898b..a552e7a224f 100644
--- a/lib/filterx/tests/test_object_string.c
+++ b/lib/filterx/tests/test_object_string.c
@@ -21,24 +21,13 @@
  *
  */
 #include <criterion/criterion.h>
+#include "libtest/filterx-lib.h"
+
 #include "filterx/object-string.h"
 #include "filterx/object-null.h"
 
 #include "apphook.h"
 #include "scratch-buffers.h"
-#include "filterx-lib.h"
-
-static void
-assert_object_json_equals(FilterXObject *obj, const gchar *expected_json_repr)
-{
-  struct json_object *jso = NULL;
-
-  cr_assert(filterx_object_map_to_json(obj, &jso) == TRUE, "error mapping to json, expected json was: %s",
-            expected_json_repr);
-  const gchar *json_repr = json_object_to_json_string_ext(jso, JSON_C_TO_STRING_PLAIN);
-  cr_assert_str_eq(json_repr, expected_json_repr);
-  json_object_put(jso);
-}
 
 Test(filterx_string, test_filterx_object_string_marshals_to_the_stored_values)
 {
diff --git a/libtest/CMakeLists.txt b/libtest/CMakeLists.txt
index b8018a38213..17ca1479baa 100644
--- a/libtest/CMakeLists.txt
+++ b/libtest/CMakeLists.txt
@@ -11,7 +11,7 @@ set(LIBTEST_HEADERS
     stopwatch.h
     cr_template.h
     grab-logging.h
-    filterx.h
+    filterx-lib.h
 )
 
 set(LIBTEST_SOURCES
@@ -28,7 +28,7 @@ set(LIBTEST_SOURCES
     stopwatch.c
     cr_template.c
     grab-logging.c
-    filterx.c
+    filterx-lib.c
 )
 
 add_library(libtest STATIC ${LIBTEST_SOURCES})
diff --git a/libtest/Makefile.am b/libtest/Makefile.am
index e23f02838c8..642c9747418 100644
--- a/libtest/Makefile.am
+++ b/libtest/Makefile.am
@@ -33,8 +33,8 @@ libtest_libsyslog_ng_test_a_SOURCES =   \
 	libtest/queue_utils_lib.h	\
 	libtest/stopwatch.c		\
 	libtest/stopwatch.h		\
-	libtest/filterx.c	\
-	libtest/filterx.h
+	libtest/filterx-lib.c	\
+	libtest/filterx-lib.h
 
 libtest_libsyslog_ng_test_a_CFLAGS = $(AM_CFLAGS) $(CRITERION_CFLAGS) $(JSON_CFLAGS)
 
@@ -50,7 +50,7 @@ libtestinclude_HEADERS		    =	\
 	libtest/proto_lib.h		\
 	libtest/queue_utils_lib.h		\
 	libtest/stopwatch.h		\
-	libtest/filterx.h
+	libtest/filterx-lib.h
 
 pkgconfig_DATA			   +=	\
 	libtest/syslog-ng-test.pc
diff --git a/libtest/filterx.c b/libtest/filterx-lib.c
similarity index 79%
rename from libtest/filterx.c
rename to libtest/filterx-lib.c
index 2c80895a40c..c1b916792e7 100644
--- a/libtest/filterx.c
+++ b/libtest/filterx-lib.c
@@ -21,9 +21,38 @@
  *
  */
 
-#include "filterx.h"
+#include <criterion/criterion.h>
+#include "filterx-lib.h"
 #include "filterx/object-json.h"
 
+void
+assert_marshaled_object(FilterXObject *obj, const gchar *repr, LogMessageValueType type)
+{
+  GString *b = g_string_sized_new(0);
+  LogMessageValueType t;
+
+  /* check if we _overwrite_ the string with the marshalled value */
+  g_string_append(b, "PREFIX");
+
+  cr_assert(filterx_object_marshal(obj, b, &t) == TRUE);
+  cr_assert_str_eq(b->str, repr);
+  cr_assert_eq(t, type);
+  g_string_free(b, TRUE);
+}
+
+void
+assert_object_json_equals(FilterXObject *obj, const gchar *expected_json_repr)
+{
+  struct json_object *jso = NULL;
+
+  cr_assert(filterx_object_map_to_json(obj, &jso) == TRUE, "error mapping to json, expected json was: %s",
+            expected_json_repr);
+  const gchar *json_repr = json_object_to_json_string_ext(jso, JSON_C_TO_STRING_PLAIN);
+  cr_assert_str_eq(json_repr, expected_json_repr);
+  json_object_put(jso);
+}
+
+
 FilterXObject *
 filterx_test_dict_new(void)
 {
diff --git a/libtest/filterx.h b/libtest/filterx-lib.h
similarity index 84%
rename from libtest/filterx.h
rename to libtest/filterx-lib.h
index 63bff0a5bc9..deeea89fc7b 100644
--- a/libtest/filterx.h
+++ b/libtest/filterx-lib.h
@@ -21,11 +21,14 @@
  *
  */
 
-#ifndef LIBTEST_FILTERX_H_INCLUDED
-#define LIBTEST_FILTERX_H_INCLUDED
+#ifndef LIBTEST_FILTERX_LIB_H_INCLUDED
+#define LIBTEST_FILTERX_LIB_H_INCLUDED
 
 #include "filterx/filterx-object.h"
 
+void assert_marshaled_object(FilterXObject *obj, const gchar *repr, LogMessageValueType type);
+void assert_object_json_equals(FilterXObject *obj, const gchar *expected_json_repr);
+
 FILTERX_DECLARE_TYPE(test_dict);
 FILTERX_DECLARE_TYPE(test_list);
 FILTERX_DECLARE_TYPE(test_unknown_object);
diff --git a/modules/json/tests/test_filterx_format_json.c b/modules/json/tests/test_filterx_format_json.c
index 6b440c68cff..956e5b252a4 100644
--- a/modules/json/tests/test_filterx_format_json.c
+++ b/modules/json/tests/test_filterx_format_json.c
@@ -22,7 +22,7 @@
 
 #include <criterion/criterion.h>
 #include "libtest/cr_template.h"
-#include "libtest/filterx.h"
+#include "libtest/filterx-lib.h"
 
 #include "filterx-format-json.h"
 #include "filterx/object-primitive.h"