CssUtil { public static String getURL(){ return CssUtil.class.getResource("/io/github/factoryfx/javafx/css/app.css").toExternalForm(); }  static void addToNode(Parent node ); static void addToScene(Scene scene ); static String getURL();  }
@Test public void test_getURL(){ System.out.println(CssUtil.getURL()); Assertions.assertNotNull(CssUtil.getURL()); }