@Test
    void testUserSpecifiedDefaultRendererIsNotReplacedInRegistry() {
        String defaultId = AbstractProcessingHandler.DEFAULT_RENDERER_ID;
        Renderer myDefaultRenderer = new ProcessingRenderer();
        ComponentRegistry<Renderer> renderers = new ComponentRegistry<>();
        renderers.register(ComponentId.fromString(defaultId), myDefaultRenderer);

        driver = new ProcessingTestDriver(List.of(), renderers);
        Renderer defaultRenderer = driver.processingHandler().getRenderers().getComponent(defaultId);
        assertSame(defaultRenderer, myDefaultRenderer);

    }
Tests that the ResponseStatus takes precedence over errors
container-core/src/test/java/com/yahoo/processing/handler/ProcessingHandlerTestCase.java