private Observable<RxBleConnection> emitConnectionWithoutCompleting() {
        connectionSubject = ReplaySubject.createWithSize(1);
        connectionSubject.onNext(rxBleConnection);
        return connectionSubject.doFinally(() -> connectionSubject = null);
    }
Set a BLE connection mock. Calling this method is required.
mockrxandroidble/src/main/java/com/polidea/rxandroidble2/mockrxandroidble/RxBleDeviceMock.java