diff --git a/src/test/test_funktionen.c b/src/test/test_funktionen.c
index 0729a16..0d2d5c9 100644
--- a/src/test/test_funktionen.c
+++ b/src/test/test_funktionen.c
@@ -11,6 +11,17 @@ void tearDown(void)
 {
 }
 
+void test_1000_plus_1(void)
+{
+    /* arrange */
+    int actual;
+    int expected = 1000;
+
+    /* act */
+    actual = addThreeNumbers(500, 249, 251);
 
+    /* assert */
+    TEST_ASSERT_EQUAL_INT(expected, actual);
+}
 
 #endif
\ No newline at end of file