Add tests to validate fixes for #1189

test/bug_fix_test.dart

@@ -0,0 +1,60 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_quill/flutter_quill.dart' hide Text;
+import 'package:flutter_test/flutter_test.dart';
+import 'widget_tester_extension.dart';
+
+void main() {
+  group('Bug fix', () {
+    group('1189 - The provided text position is not in the current node', () {
+      late QuillController controller;
+      late QuillEditor editor;
+
+      setUp(() {
+        controller = QuillController.basic();
+        editor = QuillEditor.basic(controller: controller, readOnly: false);
+      });
+
+      tearDown(() {
+        controller.dispose();
+      });
+
+      testWidgets('Refocus editor after controller clears document',
+          (tester) async {
+        await tester.pumpWidget(MaterialApp(home: Column(children: [editor])));
+        await tester.quillEnterText(find.byType(QuillEditor), 'test\n');
+
+        editor.focusNode.unfocus();
+        await tester.pump();
+        controller.clear();
+        editor.focusNode.requestFocus();
+        await tester.pump();
+        expect(tester.takeException(), isNull);
+      });
+
+      testWidgets('Refocus editor after removing block attribute',
+          (tester) async {
+        await tester.pumpWidget(MaterialApp(home: Column(children: [editor])));
+        await tester.quillEnterText(find.byType(QuillEditor), 'test\n');
+
+        controller.formatSelection(Attribute.ul);
+        editor.focusNode.unfocus();
+        await tester.pump();
+        controller.formatSelection(const ListAttribute(null));
+        editor.focusNode.requestFocus();
+        await tester.pump();
+        expect(tester.takeException(), isNull);
+      });
+
+      testWidgets('Tap checkbox in unfocused editor', (tester) async {
+        await tester.pumpWidget(MaterialApp(home: Column(children: [editor])));
+        await tester.quillEnterText(find.byType(QuillEditor), 'test\n');
+
+        controller.formatSelection(Attribute.unchecked);
+        editor.focusNode.unfocus();
+        await tester.pump();
+        await tester.tap(find.byType(CheckboxPoint));
+        expect(tester.takeException(), isNull);
+      });
+    });
+  });
+}