diff --git a/src/ageinseconds.h b/src/ageinseconds.h
index 5122b87..a490ee6 100644
--- a/src/ageinseconds.h
+++ b/src/ageinseconds.h
@@ -2,5 +2,6 @@
 #define AGEINSECONDS_H
 
 int sekunden(int jahre);
+int minuten(int jahre);
 
 #endif // AGEINSECONDS_H
diff --git a/test/test_ageinseconds.c b/test/test_ageinseconds.c
index d1acd58..90fdb9a 100644
--- a/test/test_ageinseconds.c
+++ b/test/test_ageinseconds.c
@@ -19,4 +19,11 @@ void test_ageinseconds_45_in_sekunden(void)
     TEST_ASSERT_EQUAL(1419120000, result);
 }
 
+// test minuten
+void test_ageinseconds_23_in_minuten(void)
+{
+    float result = minuten(23);
+    TEST_ASSERT_EQUAL(12088800, result);
+}
+
 #endif // TEST