create callbacks_test.dart

So far so good - this is suspicious.

packages/patrol/example/integration_test/callbacks_test.dart

@@ -0,0 +1,48 @@
+import 'package:flutter/material.dart';
+import 'package:patrol/src/extensions.dart';
+// ignore: depend_on_referenced_packages
+import 'package:test_api/src/backend/invoker.dart';
+
+import 'common.dart';
+
+String get currentTest => Invoker.current!.fullCurrentTestName();
+
+void _print(String text) => print('PATROL_DEBUG: $text');
+
+void main() {
+  patrolSetUp(() async {
+    _print('setting up before $currentTest');
+  });
+
+  patrolTearDown(() async {
+    _print('tearing down after $currentTest');
+  });
+
+  group('groupA', () {
+    patrolSetUp(() async {
+      _print('setting up before $currentTest');
+    });
+
+    patrolTearDown(() async {
+      _print('tearing down after $currentTest');
+    });
+
+    patrolTest('testA', nativeAutomation: true, _body);
+    patrolTest('testB', nativeAutomation: true, _body);
+    patrolTest('testC', nativeAutomation: true, _body);
+  });
+}
+
+Future<void> _body(PatrolTester $) async {
+  final testName = Invoker.current!.fullCurrentTestName();
+  _print('test body: name=$testName');
+
+  await createApp($);
+
+  await $(FloatingActionButton).tap();
+  expect($(#counterText).text, '1');
+
+  await $(#textField).enterText(testName);
+
+  await $.pumpAndSettle(duration: Duration(seconds: 2));
+}