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use crate::metis::{Anchor, Dotted, Locus};
use super::super::{Seq, clock, delete, insert, woven};
#[test]
fn test_anchor_for_visual_insert_returns_the_base_on_an_empty_bucket() {
// The Fugue placement rule (S127): on an EMPTY base bucket the seam returns
// the base directly (`Origin` at the document start, `After(a)` when the
// caret sits after a childless `a`), so a top rank there lands right after
// the caret.
let clk = clock(1);
let mut r: Seq = Dotted::new();
assert_eq!(r.store().anchor_for_visual_insert(None), Anchor::Origin);
// A lone element 'a' at the origin: after 'a' its After bucket is empty.
let dot_a = insert(&mut r, &clk, 1, None);
assert_eq!(
r.store().anchor_for_visual_insert(Some(dot_a.into())),
Anchor::After(dot_a.into())
);
}
#[test]
fn test_anchor_for_visual_insert_returns_before_the_successor_on_a_nonempty_bucket() {
// On a NONEMPTY base bucket the caret's in-order successor exists in the
// subtree, so the seam returns `Before(successor)` (S127). Build "cat" as a
// chain; the caret after 'a' has successor 't', so the seam hangs Before 't'.
let clk = clock(1);
let mut r: Seq = Dotted::new();
let dot_c = insert(&mut r, &clk, 1, None);
let dot_a = insert(&mut r, &clk, 1, Some(dot_c));
let dot_t = insert(&mut r, &clk, 1, Some(dot_a));
assert_eq!(
r.store().anchor_for_visual_insert(Some(dot_a.into())),
Anchor::Before(dot_t.into())
);
// At the document start the successor is the head 'c'.
assert_eq!(
r.store().anchor_for_visual_insert(None),
Anchor::Before(dot_c.into())
);
}
#[test]
fn test_anchor_for_visual_insert_descends_a_before_chain_through_a_tombstone() {
// The descent reads the SKELETON, not visibility, so the successor it finds
// may be an invisible tombstone (S127). Build 'c' then 'a' after 'c', then a
// Before-child of 'a' that we delete; the caret at the document start still
// descends past the head into the deepest Before element (the tombstone).
let clk = clock(1);
let mut r: Seq = Dotted::new();
let dot_c = insert(&mut r, &clk, 1, None);
let _dot_a = insert(&mut r, &clk, 1, Some(dot_c));
// Weave a Before-child of 'c' with a top rank so it becomes the head's
// deepest before-region element, then delete it (a tombstone the descent
// must still read through).
let before_rank = clk.now(0u16);
let dot_b = r.next_dot(1);
r = r.merge(&woven(
dot_b,
Locus {
anchor: Anchor::Before(dot_c.into()),
rank: before_rank,
},
));
delete(&mut r, dot_b);
// The document-start caret's successor is the deepest Before element down
// from the head 'c', which is the tombstone `dot_b`.
assert_eq!(
r.store().anchor_for_visual_insert(None),
Anchor::Before(dot_b.into())
);
}
#[test]
fn test_visual_insert_top_rank_lands_immediately_after_the_caret() {
// THE "catX" cure at the store level. Build "cat" as a chain, then weave 'X'
// at `anchor_for_visual_insert(Some(a))` (= `Before(t)`) with a rank ABOVE
// `children_of(that anchor)`: it lands immediately after 'a', reading "caXt".
let clk = clock(1);
let mut r: Seq = Dotted::new();
let dot_c = insert(&mut r, &clk, 1, None);
let dot_a = insert(&mut r, &clk, 1, Some(dot_c));
let dot_t = insert(&mut r, &clk, 1, Some(dot_a));
assert_eq!(r.store().order(), [dot_c, dot_a, dot_t]);
// The seam returns `Before(t)` (t is the successor of the caret after 'a').
let anchor = r.store().anchor_for_visual_insert(Some(dot_a.into()));
assert_eq!(anchor, Anchor::Before(dot_t.into()));
// The Before(t) bucket is empty, so any rank places X adjacent (right before
// t, i.e. right after 'a'); mint a fresh rank off the clock.
let dot_x = r.next_dot(1);
let rank = clk.now(0u16);
r = r.merge(&woven(dot_x, Locus { anchor, rank }));
// 'X' reads immediately after 'a' and before 't': "caXt", not "catX".
assert_eq!(r.store().order(), [dot_c, dot_a, dot_x, dot_t]);
}