You'll need to have all the [prerequisites](https://github.com/facebook/react-native/tree/master/ReactAndroid#prerequisites) (SDK, NDK) for Building React Native installed.
Start an Android emulator ([Genymotion](https://www.genymotion.com) is recommended).
Install Detox from [here](https://github.com/wix/Detox/blob/master/docs/Introduction.GettingStarted.md).
To run the e2e tests locally, run the following commands from the react-native folder:
yarn build-ios-e2e
yarn test-ios-e2e
These are the equivalent of running:
detox build -c ios.sim.release
detox test -c ios.sim.release --cleanup
These build the app in Release mode, so the production code is bundled and included in the built app.
When developing E2E tests, you may want to run in development mode, so that changes to the production code show up immediately. To do this, run:
detox build -c ios.sim.debug
detox test -c ios.sim.debug
You will also need to have Metro Bundler running in another terminal. Note that if you've previously run the E2E tests in release mode, you may need to delete the `RNTester/build` folder before rerunning `detox build`.
Building the app on both iOS and Android means building the React Native framework from source. This way you're running the latest native and JS code the way you see it in your clone of the github repo.
This is different from apps created using `react-native init` which have a dependency on a specific version of React Native JS and native code, declared in a `package.json` file (and `build.gradle` for Android apps).