@Test
    void serverProviders_are_included_in_components_config() {
        Element clusterElem = DomBuilderTest.parse(
                "<container id='default' version='1.0'>" +
                        "  <server id='discServer' />" +
                        "</container>");

        createModel(root, clusterElem);

        String componentsConfig = componentsConfig().toString();
        assertThat(componentsConfig, containsString(".id \"discServer\""));
    }
Tests for "core functionality" of the container model, e.g. ports, or the 'components' and 'bundles' configs.

Before adding a new test to this class, check if the test fits into one of the other existing subclasses
of {@link ContainerModelBuilderTestBase}. If not, consider creating a new subclass.

@author gjoranv
config-model/src/test/java/com/yahoo/vespa/model/container/xml/ContainerModelBuilderTest.java