React Native

Maestro supports testing React Native screens and apps on both Android and iOS.

Interacting with a component by Text

Maestro can interact with components that display text.

Example: Tap on a Button

For the Button component definition:

<Button
  title="Go"
  onPress={() => Alert.alert('Success!')}
/>

The following command will tap on the Button:

- tapOn: "Go"

Interaction with a component by testID

Maestro can interact with components that have a testID.

Example: Tap on a button with a testID property

For the Button component definition:

<Button
  title="Go"
  testID="continue"
  onPress={() => Alert.alert('Success!')}
/>

The following command will tap on the Button:

- tapOn:
    id: "continue"

Entering text in a Text Input

Example: Enter text into a TextInput.

To input text to a TextInput component, first the component needs to be selected. This can be done using the tapOn command. For the component definition:

<TextInput placeholder="Change me!" />

The following commands will enter "Hello, Maestro!" in the TextInput component:

- tapOn: "Change me!"
- inputText: "Hello, Maestro!"

Create a working sample app with Maestro tests

Install Maestro

Maestro install instructions

Create a sample app

Follow the Expo Go Quickstart instructions on React Native environment setup

Replace the contents of App.js with:

import React, { useState } from 'react';
import { SafeAreaView, Button, Text, TextInput, StyleSheet } from 'react-native';

export default function App() {
  const [taps, setTaps] = useState(0);
  const [text, setText] = useState('')
  return (
    <SafeAreaView>
      <Button
        title="Add one"
        variant="primary"
        onPress={() => setTaps(taps + 1)}
      />
      <Button
        title="Add ten"
        testID="add_ten"
        onPress={() => setTaps(taps + 10)}
      />
      <Text>Number of taps: {taps}</Text>
      <TextInput
        testID="text_input"
        placeholder="Change me!"
        onChangeText={setText}
      />
      <Text>You typed: {text}</Text>
    </SafeAreaView>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center',
  },
});

Create a test definition file called flow.yaml

Add the following contents:

appId: host.exp.Exponent
---
- launchApp
- tapOn: "Add one"
- tapOn:
    id: "add_ten"
- assertVisible: "Number of taps: 11"
- tapOn: "Change me!"
- inputText: "Hello, Maestro!"
- assertVisible: "You typed: Hello, Maestro!"

Start the app and test using Maestro

Run npm start in the react native app source directory

Select either Android or iOS Simulator

In another terminal, run maestro test flow.yaml

When the Expo app launches, select the app that you’re testing

Demo

28MB

Screen Recording 2023-01-11 at 21.24.32.mov

React Native app tested using Maestro

Interacting with nested components on iOS

In some cases, you may run into issues with nested tappable / accessible elements on iOS. You can resolve these issues by enabling accessibility for the inner component and disabling it for the outer container.

Example: Tapping on nested Text Component

<TouchableOpacity 
  style={{ borderWidth: 1, margin: 5, padding: 10, backgroundColor: '#ddd' }} 
   accessible={false}>
  <Text>This is the wrapper button </Text>
  <TouchableOpacity 
    style={{ backgroundColor: 'red', padding: 5, width: '50%', marginTop: 10 }} 
     accessible={true}>
    <Text>I'm a small button</Text>
  </TouchableOpacity>
</TouchableOpacity>

The following command will tap on the nested Text Component:

- tapOn: "I'm a small button"

Resources

• A great introduction to Maestro with React Native by Alexander Hodes

• E2E testing of React Native apps using EAS and Maestro (Expo documentation)