diff --git a/test/test_timer_utils.c b/test/test_timer_utils.c
index 32054c3..433daa6 100644
--- a/test/test_timer_utils.c
+++ b/test/test_timer_utils.c
@@ -1,18 +1,18 @@
 #include <stdio.h>
 #include <time.h>
+#include <inttypes.h>
 
 #include "CUnit/Basic.h"
 #include "timer_utils.h"
+#include "time_scales.h"
 
 int init_suite1(void)
 {
-	printf("init_suit1()");
 	return 0;
 }
 
 int clean_suite1(void)
 {
-	printf("clean_suit1()");
 	return 0;
 }
 
@@ -43,13 +43,51 @@ void test_add_time_3(void)
 {
 	struct itimerspec test_time = {
 		.it_value = {
-			.tv_nsec = 999999999,
+			.tv_nsec = 999999111,
 			.tv_sec = 0}};
 	tmr_add_ns_to_current_time(&test_time, 1000);
 	CU_ASSERT(test_time.it_value.tv_sec == 1);
-	CU_ASSERT(test_time.it_value.tv_nsec == 999);
+	CU_ASSERT(test_time.it_value.tv_nsec == 111);
 }
 
+void test_add_time_4(void)
+{
+	const uint32_t start = 999999990;
+	struct itimerspec time = {
+		.it_value = {
+			.tv_nsec = start,
+			.tv_sec = 0}};
+
+	for (uint32_t i = start; i < 999999999; i++)
+	{
+		tmr_add_ns_to_current_time(&time, 1);
+		printf("%u:\t", i);
+		printf("%u,%u\n", time.it_value.tv_sec, time.it_value.tv_nsec);
+		CU_ASSERT(time.it_value.tv_nsec == i + 1);
+	}
+
+	tmr_add_ns_to_current_time(&time, 1);
+	printf("1000000000:\t");
+	printf("%u,%u\n", time.it_value.tv_sec, time.it_value.tv_nsec);
+	CU_ASSERT(time.it_value.tv_nsec == 0);
+	CU_ASSERT(time.it_value.tv_sec == 1);
+}
+
+void test_big_number(void)
+{
+	struct itimerspec time = {
+		.it_value = {
+			.tv_nsec = 999999999,
+			.tv_sec = 0,
+		},
+	};
+
+	tmr_add_ns_to_current_time(&time, 1*SEC);
+	CU_ASSERT(time.it_value.tv_nsec == 999999999);
+	CU_ASSERT(time.it_value.tv_sec == 1);
+}
+
+
 int main()
 {
 	CU_pSuite pSuite = NULL;
@@ -64,14 +102,11 @@ int main()
 		return CU_get_error();
 	}
 
-	if ((NULL == CU_add_test(pSuite, "test if time is added correctly with tmr_add_ns_to_current_time()", test_add_time_1)) ||
-		(NULL == CU_add_test(pSuite, "test if time is added correctly with tmr_add_ns_to_current_time()", test_add_time_2))||
-		(NULL == CU_add_test(pSuite, "test if time is added correctly with tmr_add_ns_to_current_time()", test_add_time_3))||
-		(NULL == CU_add_test(pSuite, "test if time is added correctly with tmr_add_ns_to_current_time()", test_add_time_2)))
-	{
-		CU_cleanup_registry();
-		return CU_get_error();
-	}
+	CU_add_test(pSuite, "test if time is added correctly with tmr_add_ns_to_current_time()", test_add_time_1);
+	CU_add_test(pSuite, "test if time is added correctly with tmr_add_ns_to_current_time()", test_add_time_2);
+	CU_add_test(pSuite, "test if time is added correctly with tmr_add_ns_to_current_time()", test_add_time_3);
+	CU_add_test(pSuite, "test adding time in loop", test_add_time_4);
+	CU_add_test(pSuite, "test adding big numbers", test_big_number);
 
 	CU_basic_set_mode(CU_BRM_VERBOSE);
 	CU_basic_run_tests();