Effective Detox Testing

The Effective Detox Testing Workshop at React Advanced 2023 aims to provide attendees with practical knowledge and strategies for effective Detox testing in React Native applications. The workshop covers topics such as what to test with Detox, how to fake the API layer, running Detox on continuous integration servers, and integrating Detox into local development workflows.

The main focus of the Detox Testing Workshop is to teach participants how to effectively test React Native applications using Detox. This includes understanding what to test with Detox, faking the API layer for testing, running Detox on continuous integration servers, and incorporating Detox into local development workflows.

The prerequisites for attending the Detox Testing Workshop include having experience with React Native, understanding Detox, and being familiar with different types of tests such as unit tests, component tests, and end-to-end tests. Prior knowledge of these topics is recommended for following along with the workshop content.

To get started with Detox testing in your React Native application, you should first set up Detox and ensure it is working correctly. Then, you can create a boot test to verify that the app launches successfully. Following that, you can write play-around tests to check basic functionalities, and eventually create more comprehensive tests like happy path flows and secondary feature tests.

Using a fake API module in Detox tests allows you to simulate backend responses without relying on a real backend server. This approach reduces flakiness due to network issues, makes it easier to set up test data, and ensures that tests are more isolated and predictable. It also speeds up the testing process by eliminating the need for real HTTP requests.

To configure Detox to use a fake API module, you need to create a mock version of your API client module. Then, modify your metro.config.js file to prefer the mock module when a specific environment variable is set. Finally, create an NPM script that sets this environment variable and starts your app with the mocked API module.

Strategies for running Detox tests on continuous integration servers include picking a CI platform that supports macOS, caching dependencies to speed up builds, installing necessary dependencies, setting up node and CocoaPods, building the app for Detox, launching the simulator, and running the Detox tests. It's recommended to start with a simple boot test and gradually add more tests.

The stages for integrating Detox testing into local development workflows include: 1) Testing existing features to get initial coverage, 2) Testing new features as they are added to ensure they work correctly, and 3) Considering test-driven development (TDD) to write tests before implementing new features, thereby ensuring comprehensive test coverage and minimal production code.

The purpose of a boot test in Detox is to verify that the React Native application launches successfully without crashing. It checks that the app builds correctly and that the initial screen elements are rendered as expected. This basic test ensures that the app can start up properly, providing a foundation for more detailed tests.

A play-around test in Detox involves randomly interacting with the app to verify that basic functionalities work as expected. It is less structured and covers general usage scenarios. A happy path test, on the other hand, follows a specific user workflow from start to finish, ensuring that the most important and commonly used features of the app work correctly without errors.