public void init(CustomModel customModel, EncodedValueLookup lookup, Map<String, JsonFeature> areas) {
        this.lookup = lookup;
        this.customModel = customModel;
    }
@Test
    public void testNegativeMax() {
        CustomModel customModel = new CustomModel();
        customModel.addToSpeed(If("true", LIMIT, VehicleSpeed.key("car")));
        customModel.addToSpeed(If("road_class == PRIMARY", MULTIPLY, "0.5"));
        customModel.addToSpeed(Else(MULTIPLY, "-0.5"));

        CustomWeightingHelper helper = new CustomWeightingHelper();
        EncodingManager lookup = new EncodingManager.Builder().add(VehicleSpeed.create("car", 5, 5, true)).build();
        helper.init(customModel, lookup, null);
        IllegalArgumentException ret = assertThrows(IllegalArgumentException.class, helper::calcMaxSpeed);
        assertTrue(ret.getMessage().startsWith("statement resulted in negative value"));
    }