QuoteDecorator implements StringDecorator { @Override public String decorate(String str) { return Constants.QUOTE + str + Constants.QUOTE; }  @Override String decorate(String str);  }
@Test public void testDecorate() { System.out.println("decorate"); String result = instance.decorate("a"); assertThat(result).isEqualTo("\"a\""); result = instance.decorate(null); assertThat(result).isEqualTo("\"null\""); result = instance.decorate("b"); assertThat(result).isEqualTo("\"b\""); }