Test checkline case identical

test/test_tictactoe.c

@@ -22,4 +22,15 @@ void test_if_not_identical(void){
     TEST_ASSERT_EQUAL_CHAR(' ', result);
 }
 
+
+void test_if_identical(void){
+    /* arrange */
+    char result;
+    char a = 'a', b = 'a', c = 'a';
+
+    result = checkLine(a, b, c);
+
+    /* assert */
+    TEST_ASSERT_EQUAL_CHAR(a, result);
+}
 #endif // TEST