Patrol E2e Testing

Patrol E2E Testing Skill

Design, implement, and run end-to-end (E2E) tests using Patrol 4.x in Flutter projects.

When to Use

Use this skill when:

• A new screen or user flow needs E2E test coverage.
• A feature interacts with native components (permissions, notifications, system dialogs, deep links).
• A UI bug should be captured as a regression test.
• Cross-platform behavior (Android / iOS / Web) must be validated.
• Setting up Patrol in a new or existing Flutter project.

Setup

Follow the official Patrol documentation for installation and project initialization:

https://patrol.leancode.co/documentation#setup

Key Patrol conventions:

• Add patrol as a dev dependency.
• Place tests in patrol_test/.
• Name test files with a _test.dart suffix.
• Execute tests with patrol test.

Workflow

Follow these steps when implementing or updating Patrol tests.

1. Identify the user journey

Break the feature into:

• Actions: taps, scrolls, input, navigation, deep links.
• Observable outcomes: visible text, screen changes, enabled buttons, dialogs.

Rules:

• One test per primary (happy-path) journey.
• Separate tests for critical edge cases.
• Avoid combining unrelated flows in a single test.

2. Structure the Patrol test

Basic Patrol structure:

import 'package:flutter_test/flutter_test.dart';
import 'package:patrol/patrol.dart';

void main() {
  patrolTest(
    'user can log in successfully',
    ($) async {
      await $.pumpWidgetAndSettle(const MyApp());

      const email = String.fromEnvironment('E2E_EMAIL');
      const password = String.fromEnvironment('E2E_PASSWORD');

      await $(#emailField).enterText(email);
      await $(#passwordField).enterText(password);
      await $(#loginButton).tap();

      await $.waitUntilVisible($(#homeScreenTitle));

      expect($(#homeScreenTitle).text, equals('Welcome'));
    },
  );
}

Key concepts:

• Use patrolTest() instead of testWidgets().
• $ is the Patrol tester.
• Use $(#keyName) to find widgets by Key.
• Use explicit wait conditions (e.g., waitUntilVisible).

3. Handle native dialogs

For OS-level permission dialogs:

patrolTest('grants camera permission', ($) async {
  await $.pumpWidgetAndSettle(const MyApp());

  await $(#openCameraButton).tap();

  if (await $.native.isPermissionDialogVisible()) {
    await $.native.grantPermission();
  }

  await $.waitUntilVisible($(#cameraPreview));
});

Use native automation only when required by the feature.

4. Selector & interaction quick reference

Finding widgets:

$('some text')        // by text
$(TextField)          // by type
$(Icons.arrow_back)   // by icon

Tapping:

// Tap a widget containing a specific text label
await $(Container).$('click').tap();

// Tap a container that contains an ElevatedButton
await $(Container).containing(ElevatedButton).tap();

// Tap only the enabled ElevatedButton
await $(ElevatedButton)
    .which<ElevatedButton>(
      (b) => b.enabled,
    )
    .tap();

Entering text:

// Enter text into the second TextField on screen
await $(TextField).at(1).enterText('your input');

Scrolling:

await $(widget_you_want_to_scroll_to).scrollTo();

Native interactions:

// Grant permission while app is in use
await $.native.grantPermissionWhenInUse();

// Open notification shade and tap a notification by text
await $.native.openNotifications();
await $.native.tapOnNotificationBySelector(
  Selector(textContains: 'text'),
);

5. Running Patrol tests

Run all tests:

patrol test

Run a specific file with live reload (development mode):

patrol develop -t integration_test/my_test.dart

Run a specific file:

patrol test --target patrol_test/login_test.dart

Run on web:

patrol test --device chrome

Headless web (CI):

patrol test --device chrome --web-headless true

Filter by tags:

patrol test --tags android

6. Stabilization patterns

Flaky tests undermine confidence. Apply these patterns:

// AVOID — arbitrary delay
await Future.delayed(Duration(seconds: 3));

// PREFER — explicit wait condition
await $.waitUntilVisible($(#targetWidget));

// For animations, pump until settled
await $.pumpAndSettle();

• Never use Future.delayed as a synchronization mechanism.
• Use waitUntilVisible or waitUntilExists to wait for UI state.
• Set settleTimeout in PatrolTesterConfig for slow CI environments.

Output requirements

When applied, this skill produces:

• Patrol test(s) covering the specified feature.
• Any required widget Key additions to production code.
• Exact patrol test command(s) to execute locally.
• Notes explaining stabilization or timing decisions.

Checkpoint: Run patrol test --target <file> locally to confirm the test passes before committing.

Quality bar

A valid Patrol test must be:

• Deterministic — no arbitrary delays; uses explicit wait conditions.
• Readable — clear test name describing the user journey.
• Minimal but complete — one assertion chain per journey.
• Secret-safe — credentials loaded from String.fromEnvironment, never hardcoded.
• CI-ready — passes headless with --web-headless true or on emulator.