Detox is gray box end-to-end testing and automation library for mobile apps. It has a lot of great features:

  • Cross Platform
  • Runs on Devices
  • Automatically Synchronized
  • Test Runner Independent
  • Debuggable

Setting Up Detox

Setup Environment

Install applesimutils (Mac only)

applesimutils is a collection of utils for Apple simulators.

1brew tap wix/brew 2brew install applesimutils 3

Install Jest Globally

1npm install -g jest 2

Installation

Keep Nx Package Versions In Sync

Make sure to install the @nx/detox version that matches the version of nx in your repository. If the version numbers get out of sync, you can encounter some difficult to debug errors. You can fix Nx version mismatches with this recipe.

In any Nx workspace, you can install @nx/detox by running the following command:

❯

nx add @nx/detox

This will install the correct version of @nx/detox.

How @nx/detox Infers Tasks

The @nx/detox plugin will create a task for any project that has an ESLint configuration file present. Any of the following files will be recognized as an ESLint configuration file:

  • .detoxrc.js
  • .detoxrc.json
  • detox.config.js
  • detox.config.json

View Inferred Tasks

To view inferred tasks for a project, open the project details view in Nx Console or run nx show project my-project --web in the command line.

@nx/detox Configuration

The @nx/detox/plugin is configured in the plugins array in nx.json.

nx.json
1{ 2 "plugins": [ 3 { 4 "plugin": "@nx/detox/plugin", 5 "options": { 6 "buildTargetName": "build", 7 "startTargetName": "start", 8 "testTargetName": "test" 9 } 10 } 11 ] 12} 13

Once a Detox configuration file has been identified, the targets are created with the name you specify under buildTargetName, startTargetName or testTargetName in the nx.json plugins array. The default names for the inferred targets are build and test.

Using Detox

Testing Applications

  • Run nx test-ios frontend-e2e to build the iOS app and execute e2e tests with Detox for iOS (Mac only)
  • Run nx test-android frontend-e2e to build the Android app and execute e2e tests with Detox for Android

You can run below commands:

  • nx build-ios frontend-e2e: build the iOS app (Mac only)
  • nx build-android frontend-e2e: build the Android app

Testing against Prod Build

You can run your e2e test against a production build:

  • nx test-ios frontend-e2e --prod: to build the iOS app and execute e2e tests with Detox for iOS with Release configuration (Mac only)
  • nx test-android frontend-e2e --prod: to build the Android app and execute e2e tests with Detox for Android with release build type
  • nx build-ios frontend-e2e --prod: build the iOS app using Release configuration (Mac only)
  • nx build-android frontend-e2e --prod: build the Android app using release build type

Configuration

Using .detoxrc.json

If you need to fine tune your Detox setup, you can do so by modifying .detoxrc.json in the e2e project.

Change Testing Simulator/Emulator

For iOS, in terminal, run xcrun simctl list devices available to view a list of simulators on your Mac. To open your active simulator, run open -a simulator. In frontend-e2e/.detoxrc.json, you could change the simulator under devices.simulator.device.

For Android, in terminal, run emulator -list-avds to view a list of emulators installed. To open your emulator, run emulator -avd <your emulator name>. In frontend-e2e/.detoxrc.json, you could change the simulator under devices.emulator.device.

In addition, to override the device name specified in a configuration, you could use --device-name option: nx test-ios <app-name-e2e> --device-name "iPhone 11". The device-name property provides you the ability to test an application run on specific device.

❯

nx test-ios frontend-e2e --device-name "iPhone 11"

❯

nx test-android frontend-e2e --device-name "Pixel_4a_API_30"