Sub-second integration tests for your RN app & Bluetooth device

Soundboks makes Bluetooth speakers controlled by a phone app, including features such as equalizer settings, speaker locking, and linking multiple speakers. Its Appium setup tested real phones and speakers, but about 15 scenarios took two and a half hours to run across devices. Runs could also fail inconsistently, slowing feedback on pull requests.

Handwritten mocks for react-native-ble-plx were hard to maintain and could keep passing after the device protocol changed. Thorup’s alternative records actual Bluetooth traffic from the app and device into JSON files, then reuses those recordings in Jest tests. The result retains messages observed in real device interactions while running without physical hardware.

A lightweight React Native recorder app runs on a phone against the real device and captures commands and events. App tests load the recording, render screens with React Testing Library, and advance through labeled points to check behavior. Thorup showed a connection test that exchanged around 50 BLE messages and ran in about 200 milliseconds.

Recordings can use a canonical device ID so developers’ local devices do not create noisy file changes. For values that vary, such as battery level, the recorder can save a chosen canonical value while tests still check the actual reading against expectations. Teams can add handwritten traffic for boundary cases, and debug translations make UUIDs and encoded values easier to inspect.