diff --git a/src/test/test_funktionen.c b/src/test/test_funktionen.c
index 4ec8524..62dafa7 100644
--- a/src/test/test_funktionen.c
+++ b/src/test/test_funktionen.c
@@ -213,6 +213,21 @@ void test_x_wins_onIndex_00_01_02(void)
     TEST_ASSERT_EQUAL_INT(expected, actual);
 }
 
+void test_o_wins_onIndex_00_10_20(void)
+{
+    /* arrange */
+    int actual;
+    int expected = 1;
+    
+    char board[][3] = {{'O',' ',' '}, {'O',' ',' '}, {'O',' ',' '}};
+
+    /* act */
+    actual = o_wins_00_10_20(board);
+
+    /* assert */
+    TEST_ASSERT_EQUAL_INT(expected, actual);
+}
+
 void test_stringLaenge_von_Kokosnuss(void)
 {
     /* arrange */