TF-2953 Set up Patrol tests

integration_test/base/core_robot.dart

@@ -0,0 +1,15 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:patrol/patrol.dart';
+
+abstract class CoreRobot {
+  final PatrolIntegrationTester $;
+
+  CoreRobot(this.$);
+
+  Future<void> ensureViewVisible(PatrolFinder patrolFinder) async {
+    await $.waitUntilVisible(patrolFinder);
+    expect(patrolFinder, findsWidgets);
+  }
+
+  dynamic ignoreException() => $.tester.takeException();
+}