Android things exposes a set of APIs that enable you to control various peripherals.
The Android Things Bluetooth APIs extends the basic android bluetooth APIs that shall provide access to Bluetooth functionality and this can be used for configuration and verification of bluetooth.
At connectivity level, the connectivity manager shall be of great help in monitoring and verification of various network connectivity status and related functionalities in ethernet and wireless.
The WiFi manager APIs enable communication with wireless stack which can be used in managing/checking Wi-Fi specific operations.
In case if you want to validate your development features or driver changes on network connectivity part of stack (Bluetooth, Cellular and Wi-Fi), the Android Connectivity Testing Suite (ACTS) can help for verification of functionality and stability.