public TestRoot buildModel(DeployState deployState) {
        MapConfigModelRegistry registry = new MapConfigModelRegistry(builders);
        try {
            validate(deployState.getApplicationPackage());
            return new TestRoot(new VespaModel(registry, deployState));
        } catch (IOException | SAXException e) {
            throw new RuntimeException(e);
        }
    }
Build a model given a deploy state.

@param deployState An instance of {@link com.yahoo.config.model.deploy.DeployState}
@return a producer root capable of answering getConfig requests.
config-model/src/main/java/com/yahoo/config/model/test/TestDriver.java