test(editor-ext): cover recreateTransform invariant, table move/selection, unique-id

recreateTransform: apply(diff)==target round-trip across text/mark/structural
edits and complexSteps/wordDiffs options. moveRow/moveColumn drive real PM
tables (reorder preserves content, self-move/no-table -> false, CellSelection
on select). getSelectionRangeInColumn: single/multi-column + colspan + range
guard. addUniqueIdsToDoc: only configured types, nested targets, idempotency.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/editor-ext/src/lib/recreate-transform/recreateTransform.test.ts

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+import { describe, it, expect } from "vitest";
+import { schema } from "@tiptap/pm/schema-basic";
+import type { Node as PMNode } from "@tiptap/pm/model";
+import { Transform } from "@tiptap/pm/transform";
+import { recreateTransform } from "./recreateTransform";
+
+/**
+ * recreateTransform diffs two documents and produces ProseMirror steps that turn
+ * `fromDoc` into `toDoc`. It is the backbone of collaborative/version diffing, so
+ * THE invariant that matters is: replaying the produced steps on `fromDoc` must
+ * reproduce `toDoc` exactly. Every test below re-applies the steps onto a fresh
+ * Transform seeded from `fromDoc` (not just trusting `tr.doc`) and asserts node
+ * equality with `.eq()`. If a regression makes any step wrong, the round-trip
+ * breaks and the test fails.
+ */
+
+// Real ProseMirror schema (the standard basic schema) with paragraph/heading +
+// strong/em marks — the same primitives the editor diffs in production.
+const doc = (...c: PMNode[]) => schema.node("doc", null, c);
+const p = (...c: PMNode[]) =>
+  schema.node("paragraph", null, c.length ? c : undefined);
+const h = (level: number, ...c: PMNode[]) =>
+  schema.node("heading", { level }, c);
+const t = (text: string, ...marks: any[]) =>
+  schema.text(text, marks.length ? marks : undefined);
+const strong = schema.marks.strong.create();
+const em = schema.marks.em.create();
+
+// Replay the diff's steps onto a fresh Transform built from `fromDoc`. This is
+// the faithful "apply(diff) == target" check — it exercises the actual Step
+// objects rather than the transform's internal accumulated doc.
+function applyDiff(fromDoc: PMNode, toDoc: PMNode, options?: any): PMNode {
+  const tr = recreateTransform(fromDoc, toDoc, options);
+  const replay = new Transform(fromDoc);
+  tr.steps.forEach((s) => {
+    const result = replay.maybeStep(s);
+    if (result.failed) throw new Error(`step failed: ${result.failed}`);
+  });
+  return replay.doc;
+}
+
+describe("recreateTransform round-trip (apply(diff) == target)", () => {
+  it("reconstructs the target on plain text insertion", () => {
+    // Inserting " world" must yield exactly the target paragraph.
+    const from = doc(p(t("hello")));
+    const to = doc(p(t("hello world")));
+    expect(applyDiff(from, to).eq(to)).toBe(true);
+  });
+
+  it("reconstructs the target on text deletion", () => {
+    // Deleting a trailing word is the inverse of insertion and must round-trip.
+    const from = doc(p(t("hello world")));
+    const to = doc(p(t("hello")));
+    expect(applyDiff(from, to).eq(to)).toBe(true);
+  });
+
+  it("reconstructs the target when a word is replaced mid-string", () => {
+    // A char-level replace in the middle must not corrupt the surrounding text.
+    const from = doc(p(t("the quick brown fox")));
+    const to = doc(p(t("the slow brown fox")));
+    expect(applyDiff(from, to).eq(to)).toBe(true);
+  });
+
+  it("reconstructs the target when a mark is added (complexSteps path)", () => {
+    // Mark-only changes are diffed in a separate pass; the bolded run must match.
+    const from = doc(p(t("hello")));
+    const to = doc(p(t("hello", strong)));
+    const out = applyDiff(from, to);
+    expect(out.eq(to)).toBe(true);
+    // Sanity: the produced doc actually carries the strong mark.
+    expect(out.firstChild!.firstChild!.marks.length).toBe(1);
+  });
+
+  it("reconstructs the target when a mark is removed", () => {
+    // Removing the only mark must leave the same text with no marks.
+    const from = doc(p(t("hello", strong)));
+    const to = doc(p(t("hello")));
+    const out = applyDiff(from, to);
+    expect(out.eq(to)).toBe(true);
+    expect(out.firstChild!.firstChild!.marks.length).toBe(0);
+  });
+
+  it("reconstructs the target on a paragraph split into two blocks", () => {
+    // Structural change (one block -> two) must replay as valid replace steps.
+    const from = doc(p(t("hello world")));
+    const to = doc(p(t("hello")), p(t("world")));
+    const out = applyDiff(from, to);
+    expect(out.eq(to)).toBe(true);
+    expect(out.childCount).toBe(2);
+  });
+
+  it("reconstructs the target on a node-type change (paragraph -> heading)", () => {
+    // Type/attrs changes drive the setNodeMarkup branch; the node must become a
+    // heading while keeping its text.
+    const from = doc(p(t("hello")));
+    const to = doc(h(1, t("hello")));
+    const out = applyDiff(from, to);
+    expect(out.eq(to)).toBe(true);
+    expect(out.firstChild!.type.name).toBe("heading");
+  });
+
+  it("reconstructs a combined structural + mark change", () => {
+    // Several diff kinds at once (new block + italic run) still round-trips.
+    const from = doc(p(t("alpha")));
+    const to = doc(p(t("alpha")), p(t("beta", em)));
+    const out = applyDiff(from, to);
+    expect(out.eq(to)).toBe(true);
+  });
+
+  it("produces an empty step list for identical documents", () => {
+    // No diff => no work; spurious steps would mean wasted/incorrect history.
+    const from = doc(p(t("same")));
+    const to = doc(p(t("same")));
+    const tr = recreateTransform(from, to);
+    expect(tr.steps.length).toBe(0);
+    expect(tr.doc.eq(to)).toBe(true);
+  });
+
+  it("round-trips with complexSteps:false (marks diffed as replaces)", () => {
+    // With complexSteps off, mark changes are folded into replace steps rather
+    // than dedicated mark steps — the result must still equal the target.
+    const from = doc(p(t("hello")));
+    const to = doc(p(t("hello", strong)));
+    expect(applyDiff(from, to, { complexSteps: false }).eq(to)).toBe(true);
+  });
+
+  it("round-trips with wordDiffs:true (whole-word text diffing)", () => {
+    // wordDiffs changes the granularity of the text diff, not the outcome.
+    const from = doc(p(t("the quick brown fox")));
+    const to = doc(p(t("the quick red fox")));
+    expect(applyDiff(from, to, { wordDiffs: true }).eq(to)).toBe(true);
+  });
+});