fix: redo/undo error

frontend/app_flowy/packages/appflowy_editor/test/legacy/undo_manager_test.dart

@@ -0,0 +1,76 @@
+import 'dart:collection';
+import 'package:appflowy_editor/appflowy_editor.dart';
+import 'package:appflowy_editor/src/undo_manager.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() async {
+  setUpAll(() {
+    TestWidgetsFlutterBinding.ensureInitialized();
+  });
+
+  Node _createEmptyEditorRoot() {
+    return Node(
+      type: 'editor',
+      children: LinkedList(),
+      attributes: {},
+    );
+  }
+
+  test("HistoryItem #1", () {
+    final document = StateTree(root: _createEmptyEditorRoot());
+    final editorState = EditorState(document: document);
+
+    final historyItem = HistoryItem();
+    historyItem.add(DeleteOperation(
+        [0], [TextNode(type: 'text', delta: Delta()..insert('0'))]));
+    historyItem.add(DeleteOperation(
+        [0], [TextNode(type: 'text', delta: Delta()..insert('1'))]));
+    historyItem.add(DeleteOperation(
+        [0], [TextNode(type: 'text', delta: Delta()..insert('2'))]));
+
+    final transaction = historyItem.toTransaction(editorState);
+    assert(isInsertAndPathEqual(transaction.operations[0], [0], '2'));
+    assert(isInsertAndPathEqual(transaction.operations[1], [0], '1'));
+    assert(isInsertAndPathEqual(transaction.operations[2], [0], '0'));
+  });
+
+  test("HistoryItem #2", () {
+    final document = StateTree(root: _createEmptyEditorRoot());
+    final editorState = EditorState(document: document);
+
+    final historyItem = HistoryItem();
+    historyItem.add(DeleteOperation(
+        [0], [TextNode(type: 'text', delta: Delta()..insert('0'))]));
+    historyItem
+        .add(UpdateOperation([0], {"subType": "number"}, {"subType": null}));
+    historyItem.add(DeleteOperation([0], [TextNode.empty(), TextNode.empty()]));
+    historyItem.add(DeleteOperation([0], [TextNode.empty()]));
+
+    final transaction = historyItem.toTransaction(editorState);
+    assert(isInsertAndPathEqual(transaction.operations[0], [0]));
+    assert(isInsertAndPathEqual(transaction.operations[1], [0]));
+    assert(transaction.operations[2] is UpdateOperation);
+    assert(isInsertAndPathEqual(transaction.operations[3], [0], '0'));
+  });
+}
+
+bool isInsertAndPathEqual(Operation operation, Path path, [String? content]) {
+  if (operation is! InsertOperation) {
+    return false;
+  }
+
+  if (!pathEquals(operation.path, path)) {
+    return false;
+  }
+
+  final firstNode = operation.nodes[0];
+  if (firstNode is! TextNode) {
+    return false;
+  }
+
+  if (content == null) {
+    return true;
+  }
+
+  return firstNode.delta.toRawString() == content;
+}