diff --git a/src/test/test_funktionen.c b/src/test/test_funktionen.c
index 3031ebb..0281608 100644
--- a/src/test/test_funktionen.c
+++ b/src/test/test_funktionen.c
@@ -350,6 +350,21 @@ void test_o_wins_onIndex_10_11_12(void)
     TEST_ASSERT_EQUAL_INT(expected, actual);
 }
 
+void test_o_wins_onIndex_20_21_22(void)
+{
+    /* arrange */
+    int actual;
+    int expected = 1;
+    
+    char board[][3] = {{' ',' ',' '}, {' ',' ',' '}, {'O','O','O'}};
+
+    /* act */
+    actual = o_wins_20_21_22(board);
+
+    /* assert */
+    TEST_ASSERT_EQUAL_INT(expected, actual);
+}
+
 void test_stringLaenge_von_Kokosnuss(void)
 {
     /* arrange */