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Introducing Maestro: The Evolution of Mobile UI Testing




In the field of mobile application development, maintaining the highest levels of user experience is paramount. To ensure this, developers must thoroughly test the user interface (UI) of their applications. The process of UI testing, however, can be time-consuming and complex, particularly when dealing with the inherent instability and delays of mobile applications. This is where Maestro comes in.

Maestro, a groundbreaking open-source mobile UI testing framework, has been making waves in the development community. Its efficient, user-friendly approach to automating mobile UI tests sets Maestro apart from its predecessors and has established it as a game-changer in the field.

Why Maestro Stands Out

Maestro’s simplicity and efficiency are its most notable features. Built on the learning from its predecessors, namely Appium, Espresso, UIAutomator, and XCTest, Maestro has streamlined the mobile UI testing process significantly. It offers a host of advantages that make it a preferred choice for many developers.

Embracing Instability

One of the biggest challenges in mobile UI testing is dealing with the inherent flakiness of UI elements in mobile apps. Elements may not always be located where expected, and screen taps might not always register. Unlike other frameworks that struggle with these issues, Maestro embraces this instability and is designed to counter it effectively.

Tolerance to Delays

Delays are another common issue in mobile app testing, often caused by the time it takes to load content over the network. Maestro eliminates the need for developers to intersperse their tests with sleep() calls to accommodate these delays. Instead, it automatically waits for content to load, but not longer than required, making the testing process smoother and faster.

Rapid Iteration

Maestro’s ability to interpret tests negates the need for compiling anything. It continuously monitors test files and reruns them as they change, fostering a blazingly fast iteration process.

Declarative Syntax

Maestro allows developers to define their tests in a YAML file. The syntax is clear, uncomplicated, and human-readable, which simplifies the process of writing, understanding, and maintaining tests.

Cross-Platform Compatibility

Maestro supports native (Android and iOS) and cross-platform mobile platforms (ReactNative and Flutter), making it a versatile tool for developers working on various platforms.

Getting Started with Maestro

Setting up Maestro is straightforward, and it works on multiple operating systems, including macOS, Linux, and Windows.

Installation on macOS and Linux

For iOS, install the Facebook IDB tool:

$ brew install facebook/fb/idb-companion

Ensure that your Android Emulator and iOS Simulator are booted.

Next, install the Maestro CLI using the following command:

$ curl -Ls "https://get.maestro.Mobile.dev" | bash

Following this, run the command:

$ export PATH="$PATH":"$HOME/.maestro/bin"

You can verify successful installation by checking the version of Maestro.

Installation on Windows

The installation process on Windows is slightly different and will be elaborated on in the official Maestro documentation.

Writing Your First Maestro Test

Writing tests in Maestro is straightforward, thanks to its declarative syntax and use of YAML files. Let’s go through a simple example of a test flow.

Consider a simple login Android application. The user journey or ‘flow’ that needs to be tested involves opening the application, entering the email and password, verifying the visibility of the login button, and then clicking on it.

This flow can be defined in a YAML file as follows:

appId: com.example.app

- launchApp:

appId: "com.example.app"

stopApp: true

clearState: true

- inputRandomEmail

- tapOn: "password"

- inputRandomText

- assertVisible: "LOGIN"

- tapOn: "LOGIN"

- stopApp

In this YAML file, the appId is the ID of the application to be tested. The launchApp command launches the app, stops it if it’s already running, and clears its state to ensure a fresh start. The inputRandomEmail and inputRandomText commands enter random text in the email and password fields, respectively. The assertVisible command checks if the login button is visible, and the tapOn command clicks on it. Finally, the stopApp command stops the application.

Running Maestro Tests

To run a Maestro test, you first need to build and install the app on the emulator or device.

$ adb install app/build/outputs/apk/debug/app-debug.apk

Once the app is successfully installed, you can run the flow from the command line using the following command:

$ maestro test --format junit --output results.xml .maestro

This command runs the flow, along with any other YAML files you have, and generates a JUnit report for your tests.

Maestro Cloud

One of the standout features of Maestro is the Maestro Cloud, which lets you run your flows in the cloud without the need to configure any simulators or emulators. You can integrate Maestro Cloud into your existing CI workflows easily.

Maestro Cloud offers features like parallel test execution, managed iOS simulators and Android emulators, screen recordings, Maestro command output, and application logs.

To use Maestro Cloud, you need to create an account and obtain an API Key from the Console. You can then run your tests on Maestro Cloud using the following command:

$ maestro cloud app/build/outputs/apk/debug/app-debug.apk .maestro/

Integration with Bitrise

Maestro can be integrated with Bitrise, a Mobile DevOps platform that helps developers deliver secure mobile apps faster. This integration allows you to run your Maestro flows on Bitrise quickly and easily.


Maestro represents the evolution of mobile UI testing, offering an efficient, user-friendly solution that makes automating mobile UI tests a breeze. Its ongoing development, like the upcoming maestro (2023 film), promises continuous improvement and enhancement. Whether you are a seasoned developer or a beginner, Maestro’s simplicity and efficiency make it a tool worth exploring.


To learn more about Maestro, you can check out the following resources:

Mehdi Shokoohi

Software Quality Engineer

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