Maestro - Swiss Knife for testing, accessibility, screnshots & supports Flutter

Maestro (from mobile.dev, often referred to as maestro.dev) is an open-source UI testing framework for mobile apps, including Flutter apps on Android and iOS, but also Web with the super-ability to automate end-to-end tests using simple YAML flows, interacting with your app via accesibility semantics labels, text, or identifiers and also have the featur to create screenshots.

– It does not give you code coverage

But

+ It elevates your thinking to use accessibility every day.
+ Allows testing flows
+ can be used by non-tech to jump from manual to automated QA
+ can create screenshots

How to Generate Screenshots (Images) of Your Flutter App Using Maestro

Set Up Maestro
Install Maestro via curl (follow the official guide):
```
curl -Ls "https://get.maestro.mobile.dev" | bash
```
Ensure your Flutter app is built:
- Android: flutter build apk
- iOS: flutter build ios (on macOS)
Add Semantics to Your Flutter Widgets (Recommended for Reliable Interaction)
Maestro relies on accessibility/semantics for Flutter. Wrap widgets with Semantics or use semanticLabel:
```
Semantics(
  label: 'Login Button',
  child: ElevatedButton(onPressed: () {}, child: Text('Login')),
)
```

Create a YAML Flow File (e.g., screenshots.yaml)
Define steps to navigate your app and take screenshots at key points:

appId: com.example.yourapp  # Your Flutter app's bundle ID
---
- launchApp
- tapOn: "Home Tab"  # Uses semantics label or text
- takeScreenshot: home_screen.png  # Saves screenshot to current directory
- swipe:
    from:
      x: 50%
      y: 80%
    to:
      x: 50%
      y: 20%
    duration: 1000
- takeScreenshot: detail_screen.png
- inputText: "Search query"
- tapOn: "Search Button"
- takeScreenshot: search_results.png

Run the Flow
Start an emulator/simulator or connect a device, then:
```
maestro test screenshots.yaml
```
Screenshots (PNG images) will be saved in your working directory.
Advanced Options
- Use Maestro Studio for visual recording: maestro studio — interact with your app, and it auto-generates commands (including screenshots).
- Run on cloud for multiple devices: Upload to Maestro Cloud.
- For automated screenshot suites (e.g., app store assets): Chain multiple takeScreenshot commands after navigating to different locales, themes, or screens.

Showcase of screenshoting: https://youtu.be/RB-QtyjV_a0 For full Maestro docs: https://maestro.mobile.dev