@Override
    public double calculateDistance(int txPower, double rssi) {
        if (mDistanceCalculator == null) {
            LogManager.w(TAG, "distance calculator has not been set");
            return -1.0;
        }
        return mDistanceCalculator.calculateDistance(txPower, rssi);
    }
@Test
    public void testCalculatesDistance() {
        org.robolectric.shadows.ShadowLog.stream = System.err;

        ModelSpecificDistanceCalculator distanceCalculator = new ModelSpecificDistanceCalculator(null, null);
        Double distance = distanceCalculator.calculateDistance(-59, -59);
        assertEquals("Distance should be 1.0 for same power and rssi", 1.0, distance, 0.1);
    }