feat: undo/redo, chargement IntersectionObserver et ARIA pour la visionneuse XLSX #154

tests/frontend/xlsx-viewer.test.mjs

@@ -842,6 +842,7 @@ await test("a read-only workbook shows the read-only pill and offers no editing"
   assert.ok(pill.textContent.includes(FR["xlsx.readonly_badge"]), pill.textContent);
   assert.equal(area.querySelector("#xlsx-tab-add"), null, "no + for read-only");
   assert.equal(area.querySelector("#xlsx-structure-btn"), null, "no structure for read-only");
+  assert.equal(area.querySelector("#xlsx-undo-btn"), null, "no history for read-only");
   assert.equal(area.querySelector('td[data-cell="A1"]').getAttribute("contenteditable"), null, "cells are not editable");
 });
 
@@ -870,6 +871,42 @@ await test("the command bar exposes grouped actions with a primary save", () =>
   assert.ok(area.querySelector(".xlsx-cmd-group[data-group='file']"));
 });
 
+// ── #154-A4 — undo/redo, ARIA ───────────────────────────────────────────────
+
+await test("undo/redo restores cell edits from the command stack", () => {
+  const area = mount();
+  const td = area.querySelector('td[data-cell="A1"]');
+  const undoBtn = area.querySelector("#xlsx-undo-btn");
+  const redoBtn = area.querySelector("#xlsx-redo-btn");
+  assert.equal(undoBtn.disabled, true, "nothing to undo yet");
+  td.focus();
+  editCell(area, "A1", "42");
+  td.dispatchEvent(new w.Event("blur"));
+  assert.equal(undoBtn.disabled, false, "undo becomes available after a committed edit");
+  undoBtn.click();
+  assert.equal(td.textContent, "100", "undo restores the original value");
+  assert.equal(area.querySelectorAll("td.xlsx-dirty").length, 0, "the cell is clean again");
+  assert.equal(redoBtn.disabled, false, "redo becomes available");
+  redoBtn.click();
+  assert.equal(td.textContent, "42", "redo reapplies the edit");
+  assert.equal(area.querySelectorAll("td.xlsx-dirty").length, 1, "the edit is dirty again");
+});
+
+await test("a no-op undo/redo pair leaves the buttons disabled", () => {
+  const area = mount();
+  assert.equal(area.querySelector("#xlsx-undo-btn").disabled, true);
+  assert.equal(area.querySelector("#xlsx-redo-btn").disabled, true);
+});
+
+await test("the grid exposes ARIA grid semantics", () => {
+  const area = mount();
+  const table = area.querySelector(".xlsx-table");
+  assert.equal(table.getAttribute("role"), "grid");
+  assert.equal(area.querySelector(".xlsx-table thead th").getAttribute("role"), "columnheader");
+  assert.equal(area.querySelector('td[data-cell="A1"]').getAttribute("role"), "gridcell");
+  assert.equal(area.querySelector("th.xlsx-rownum").getAttribute("role"), "rowheader");
+});
+
 // ── Report ──────────────────────────────────────────────────────────────────
 console.log(`\n${passCount}/${testCount} tests passed\n`);
 process.exit(passCount === testCount ? 0 : 1);