Maestro Mobile E2E Testing

Overview

Maestro is a declarative YAML-based mobile E2E testing framework. It provides automatic waiting, built-in retry logic, and fast execution without boilerplate. It's more stable than Detox or Appium for React Native apps.

Key Features

• Declarative YAML — no imperative test code, just steps
• Automatic waiting — no manual sleep() or flaky waits
• Built-in retry — reduces test flakiness
• Fast execution — runs quickly without setup overhead
• Maestro Studio — interactive test builder (maestro studio)
• Sub-flows — reusable YAML sequences for DRY tests
• JavaScript scripting — GraalJS runtime for HTTP calls and data manipulation
• Maestro Cloud — real device testing in CI without local simulators

Quick Start

Install

curl -Ls "https://get.maestro.mobile.dev" | bash
brew install openjdk@17
export JAVA_HOME=/opt/homebrew/opt/openjdk@17/libexec/openjdk.jdk/Contents/Home

Minimal test

appId: com.myapp
---
- launchApp
- tapOn:
    id: "my-button"
- assertVisible: "Expected Text"

Run

maestro test .maestro/smoke-test.yaml
maestro test --debug .maestro/smoke-test.yaml  # step through
maestro studio                                  # interactive builder

Pattern Index

Test File Template

# {Feature} {Action} Test
#
# Tests: {what this validates}
# Prerequisites:
# - Simulator/emulator running with app installed
# - Backend or mock server running (if API-dependent)

appId: com.myapp
env:
  TEST_EMAIL: maestro-{feature}@example.com
  EMAIL_SERVICE_URL: http://localhost:8025
---
# ==========================================
# STEP 1: LAUNCH + AUTH PRE-FLIGHT
# ==========================================

- launchApp

- swipe:
    direction: DOWN
    duration: 100

- extendedWaitUntil:
    visible:
      id: "auth-loaded"
    timeout: 15000

- takeScreenshot: 01-initial-state

# ==========================================
# STEP 2: {ACTION}
# ==========================================

- tapOn:
    id: "target-element"

# ==========================================
# STEP 3: VERIFY
# ==========================================

- extendedWaitUntil:
    visible:
      id: "expected-result"
    timeout: 5000

- takeScreenshot: 02-final-state

Example Output

Running a Maestro test produces output like this:

$ maestro test .maestro/smoke-test.yaml

 ║
 ║  > Flow: .maestro/smoke-test.yaml
 ║
 ║    ✅  Launch app "com.myapp"
 ║    ✅  Swipe from center to bottom
 ║    ✅  Wait until "auth-loaded" is visible (timeout: 15s)
 ║    ✅  Take screenshot "01-initial-state"
 ║    ✅  Tap on "tab-home"
 ║    ✅  Wait until "dashboard-header" is visible (timeout: 5s)
 ║    ✅  Tap on "action-button"
 ║    ✅  Wait until "undo-button" is visible (timeout: 3s)
 ║    ✅  Take screenshot "02-final-state"
 ║
 ║    Duration: 8.2s
 ║    Status: ✅ PASSED

Screenshots are saved to ~/.maestro/tests/{timestamp}/.

Folder Structure

.maestro/
├── README.md                    # Quick reference + testID inventory
├── config.yaml                  # Shared configuration
├── flows/                       # Reusable sub-flows
│   ├── auth-and-return.yaml
│   ├── complete-action.yaml
│   └── verify-result.yaml
├── scripts/                     # GraalJS helpers
│   ├── fetch-otp.js
│   └── split-otp.js
├── smoke-test.yaml              # Guest navigation
├── auth-signin.yaml             # OTP sign-in flow
├── feature-screenshots.yaml     # Screenshot capture flows
└── feature-action.yaml          # Feature-specific tests

scripts/
├── mock-api-server.ts           # Lightweight mock for E2E
└── run-e2e.sh                   # Orchestration script

Naming Conventions

Troubleshooting

Device Not Found

Error: No devices found

Cause: No simulator/emulator running, or Maestro can't detect it.

Fix:

• iOS: Open Xcode > Window > Devices and Simulators > boot a simulator, or run xcrun simctl boot "iPhone 16"
• Android: Start emulator with emulator -avd <name> or open Android Studio > Device Manager
• Verify with maestro devices (should list at least one device)

Element Not Found

Error: Element not found: id "my-button"

Cause: The element hasn't rendered yet, the testID is wrong, or a native alert is blocking it.

Fix:

1. Run maestro hierarchy to see all elements on screen — check if your element exists
2. Use maestro studio to interactively explore the element tree
3. Add extendedWaitUntil before the interaction (the element may need time to render)
4. Check if a native alert or permission dialog is blocking — add tapOn: text: "OK" optional: true before your step
5. Verify the testID is actually set in your React Native component (testID="my-button")

Flaky Tests

Symptoms: Test passes sometimes, fails other times.

Common causes and fixes:

• Race conditions: Add auth pre-flight pattern (Pattern 2) — don't interact before auth resolves
• Animations: Use extendedWaitUntil instead of fixed sleep calls
• Network dependency: Start a mock API server instead of relying on real backends
• iOS cold boot crash: Add the post-launch swipe (see gotchas.md)
• Optional elements: Don't use optional: true unless the action is genuinely optional

Checklist for New Tests

[ ] Unique test email (maestro-{feature}@example.com)
[ ] Selector strategy chosen (testID for i18n, text for single-language)
[ ] Auth pre-flight pattern used (auth-loaded)
[ ] Post-launch swipe added (iOS crash prevention)
[ ] Both auth states handled (adaptive flows)
[ ] Native alerts dismissed after mutations
[ ] Short timeouts for optimistic updates (3-5s)
[ ] Sub-flows created for reusable sequences
[ ] Descriptive screenshots at key points
[ ] Header comment with prerequisites
[ ] Mock API server started if backend-dependent
[ ] Tags added for CI filtering (ci, smoke, wip)

Debugging

maestro test --debug .maestro/test.yaml   # Step through interactively
maestro record .maestro/test.yaml          # Record as video
maestro studio                             # Interactive UI builder
maestro hierarchy                          # View element tree

Resources

• Maestro Documentation
• Maestro Selectors Reference
• Maestro Cloud
• Maestro MCP Server
• Maestro GitHub
• GraalJS HTTP Requests
• Conditions & Adaptive Flows
• GitHub Actions Integration