add depth_of test

src/logic/future_moves.rs

@@ -158,13 +158,13 @@ impl FutureMoves {
     /// Given an index from `self.arena`, what depth is it at? 0-indexed
     fn depth_of(&self, node_idx: usize) -> usize {
         let mut depth = 0;
-        let mut current = self.arena[node_idx].parent;
+        let mut current = Some(node_idx);
         while let Some(parent_idx) = current {
             depth += 1;
             current = self.arena[parent_idx].parent;
         }
 
-        depth
+        depth - 1
     }
 
     /// Compute `Move.value`, propegating upwards from the furthest out Moves
@@ -491,4 +491,72 @@ mod tests {
             "extend_layer didn't grow arena after refocus"
         );
     }
+
+    #[test]
+    fn depth_of_test() {
+        let mut futm = FutureMoves::new(Piece::Black, 0, 0);
+
+        futm.arena.push(Move {
+            i: 0,
+            j: 0,
+            board: Board::new(),
+            winner: Winner::None,
+            parent: None,
+            children: vec![1],
+            value: 0,
+            self_value: 0,
+            color: Piece::Black,
+            lazy_children: false,
+        });
+
+        futm.update_root_idx_raw(0);
+
+        // child 1
+        futm.arena.push(Move::new(
+            0,
+            0,
+            Board::new(),
+            Piece::White,
+            false,
+            Piece::Black,
+            Some(0),
+        ));
+        futm.arena[1].parent = Some(0);
+        futm.arena[1].children = vec![3];
+
+        // dummy
+        futm.arena.push(Move::new(
+            1234,
+            1234,
+            Board::new(),
+            Piece::White,
+            false,
+            Piece::Black,
+            None,
+        ));
+
+        futm.arena.push(Move::new(
+            0,
+            0,
+            Board::new(),
+            Piece::White,
+            false,
+            Piece::Black,
+            Some(0),
+        ));
+
+        futm.arena[3].parent = Some(1);
+
+        futm.arena.push(Move::new(
+            0,
+            0,
+            Board::new(),
+            Piece::White,
+            false,
+            Piece::Black,
+            Some(0),
+        ));
+
+        assert_eq!(futm.depth_of(3), 2);
+    }
 }