Real World e2e Testing With Detox

Novak describes Detox as an open-source gray-box testing framework from Wix. In his team’s React Native app, slightly more than 80 end-to-end tests took over 25 minutes to run in CI across two simulators. Tests use React Native `testID` props to find elements, then apply actions and expectations; Detox can wait for network and rendering activity it observes.

Novak says each test suite should create the users and data it needs automatically, rather than depend on manual server setup. Tests running on parallel feature branches should use unique data or isolated server instances, such as disposable Docker containers. Keeping generated data can help with debugging.

For read-only checks on the same item, Novak recommends considering `beforeAll` so user creation and navigation are not repeated for each assertion. Tests that change or delete shared data may need `beforeEach` instead. He also shows how tests that build on earlier shopping-cart steps become order-dependent; teams can repeat setup in smaller tests or combine a flow into one longer test.

Novak recommends historical reporting to spot unreliable tests and catch missing test runs, such as when a renamed file caused the team to run fewer tests than expected. He suggests using Xcode’s Debug View Hierarchy, Android Studio’s Layout Inspector, and Node’s inspector to investigate failures. Setup code can also be the source of flaky results, so it may need its own tests; Detox logs, synchronization debugging, and video recordings can help diagnose issues.

A failed test can leave the app in a state that causes later tests to fail too. Novak describes a top-level logout control that lets tests return to a known login screen, and deep links that skip lengthy navigation. He recommends readable conventions for user actions and expectations, notes that Detox cannot control dialogs from other apps or processes, and says end-to-end testing takes time and patience but can catch bugs.