Fix tests

Author: EbbDrop

src/day18.rs

@@ -420,7 +420,7 @@ mod tests {
 
     #[test]
     fn example_part2() {
-        assert_eq!(part2(EXAMPLE), "");
+        assert_eq!(part2(EXAMPLE), "6,1");
     }
 
     #[test]

tests/test_days.rs

@@ -50,5 +50,5 @@ benches!(
     15 => ("1398947", "1397393"),
     16 => ("106512", "563"),
     17 => ("3,6,3,7,0,7,0,3,0", "136904920099226"),
-    18 => ("338", ""),
+    18 => ("338", "20,44"),
 );