void () { DomExtenderEP ep = new DomExtenderEP(Bar.class.getName(), new DefaultPluginDescriptor(PluginId.getId("testDomExtension"), getClass().getClassLoader())); ep.domClassName = Bar.class.getName(); ep.extenderClassName = TestExtender.class.getName(); ServiceContainerUtil.registerExtension(ApplicationManager.getApplication(), DomExtenderEP.EP_NAME, ep, myFixture.getTestRootDisposable()); doBuilderTest("extender.xml", """ File:foo Element:foo Element:bar Attribute:extend:xxx Element:bar """); }