@Override
    public MODEL build(ConfigModelInstanceFactory<MODEL> factory, Element spec, ConfigModelContext context) {
        VespaDomBuilder.DomSimpleConfigProducerBuilder builder = new VespaDomBuilder.DomSimpleConfigProducerBuilder(context.getProducerId());
        TreeConfigProducer<AnyConfigProducer> producer = builder.build(context.getDeployState(), context.getParentProducer(), spec);
        return super.build(factory, spec, context.withParent(producer));
    }
@Test
    void testThatProducerIsInserted() {
        String services = "<foo><config name=\"bar.foo\"><key>value</key></config></foo>";
        ModelBuilder builder = new ModelBuilder();
        Model model = builder.build(DeployState.createTestState(new MockApplicationPackage.Builder().withServices(services).build()),
                null, null, new MockRoot(), XML.getDocument(services).getDocumentElement());
        assertEquals(1, model.getContext().getParentProducer().getUserConfigs().size());
    }