message: some ascii fun
diff: @@ -362,10 +362,35 @@ mod tests {
  let (mut tree, root) = generated(9);
  let delete_tx = tree.truncate_leaf(root);
  + // initial tree:
  + //
  + // (-------16g------)
  + // / \
  + // (--------14-------) \
  + // / \ \
  + // ( 6 ) ( 13 ) \
  + // / \ / \ \
  + // (2) (5) (9) (12) \
  + // / \ / \ / \ / \ \
  + // (0) (1) (3) (4) (7) (8) (10) (11) (15)
  + //
  + // new tree:
  + // (--------14-------)
  + // / \
  + // ( 6 ) ( 13 )
  + // / \ / \
  + // (2) (5) (9) (12)
  + // / \ / \ / \ / \
  + // (0) (1) (3) (4) (7) (8) (10) (11)
  + //
  + // so (15) is truncated
  + // and new root, (14) is a stored one now
  +
  match delete_tx.new_root {
  NodeLink::Stored(14) => { /* ok */ },
  _ => panic!("Root should be stored(14)")
  }
  + assert_eq!(tree.len(), 15);
  }
  #[test]
  @@ -373,11 +398,36 @@ mod tests {
  let (mut tree, root) = generated(10);
  let delete_tx = tree.truncate_leaf(root);
  + // initial tree:
  + //
  + // (--------18g--------)
  + // / \
  + // (--------14-------) \
  + // / \ \
  + // ( 6 ) ( 13 ) \
  + // / \ / \ \
  + // (2) (5) (9) (12) (17)
  + // / \ / \ / \ / \ / \
  + // (0) (1) (3) (4) (7) (8) (10) (11) (15) (16)
  + //
  + // new tree:
  + // (-------16g------)
  + // / \
  + // (--------14-------) \
  + // / \ \
  + // ( 6 ) ( 13 ) \
  + // / \ / \ \
  + // (2) (5) (9) (12) \
  + // / \ / \ / \ / \ \
  + // (0) (1) (3) (4) (7) (8) (10) (11) (15)
  +
  + // new root is generated
  match delete_tx.new_root {
  NodeLink::Generated(_) => { /* ok */ },
  _ => panic!("Root now should be generated")
  }
  + // left is 14 and right is 15
  let (left_root_child, right_root_child) = {
  let root = tree.resolve_link(delete_tx.new_root);
  @@ -386,12 +436,10 @@ mod tests {
  root.node.right.expect("there should be right child for root"),
  )
  };
  -
  match (left_root_child, right_root_child) {
  (NodeLink::Stored(14), NodeLink::Stored(15)) => { /* ok */ },
  _ => panic!("Root should have s(14) and s(15) children")
  };
  -
  assert_eq!(delete_tx.truncated, 2);
  assert_eq!(tree.len(), 16);
  }
  