diff --git a/test/test_timedelta.c b/test/test_timedelta.c
index 0f9da8a776f657f6a6e4376cd0ebd34b4824b253..b5132a92bb76a1bc1df8646b1f7689f6f296a964 100644
--- a/test/test_timedelta.c
+++ b/test/test_timedelta.c
@@ -16,7 +16,7 @@
 #include "mtime_julianDay.h"
 
 /**
- * check the string representation of mtime variables of type 
+ * check the string representation of mtime variables of type
  * datetime and timedelta
  */
 static void test_mtime_string_representation() {
@@ -51,6 +51,7 @@ static void test_mtime_string_representation() {
   assert_string_equal("P1Y06M",timedeltaToString(td,tds));
 
 }
+
 /**
  * test the addition of a month uppon the and of january
  */
@@ -194,6 +195,9 @@ static void test_event_at_endOfMonths() {
     } while (compareDatetime(model_time, stop_date) <= 0);
 }
 
+/**
+ * check adding negative time periods
+ */
 static void test_add_delta(){
   struct _datetime *dummy;
   struct _datetime *init = newDateTime("1111-11-11T00:00:00.000");
@@ -206,6 +210,7 @@ static void test_add_delta(){
   assert_string_equal("1111-11-11T00:10:00.000",datetimeToString(addTimeDeltaToDateTime(init,minusdelta,init),init_s));
   assert_string_equal("1111-11-11T00:00:00.000",datetimeToString(addTimeDeltaToDateTime(init,minusdelta,init),init_s));
 }
+
 int main(void) {
   initCalendar(PROLEPTIC_GREGORIAN);