ViewResponseFilter implements ContainerResponseFilter { private String appendExtensionIfRequired(String viewName) { return appendExtensionIfRequired(viewName, ozarkConfig.getDefaultViewFileExtension()); }  @Override void filter(ContainerRequestContext requestContext,
                       ContainerResponseContext responseContext);  }
@Test public void testAppendExtensionIfRequired() { String actualViewName = ViewResponseFilter.appendExtensionIfRequired(viewName, defaultExtension); assertEquals(expectedViewName, actualViewName); }