### Question:
DefaultValueListBoxRenderer implements Renderer<T> { @Override public String render(T value) { if(values == null || !values.containsKey(value)) { return NULL_STR; } return values.get(value); }  void setValues(Map<T, String> values); @Override String render(T value); @Override void render(T value,
                       Appendable appendable); static final String NULL_STR; }### Answer:
@Test public void testRenderWithoutOptions() throws Exception { renderer.render(NON_EXISTING_OPTION, appendable); verify(renderer, times(1)).render(NON_EXISTING_OPTION); verify(appendable, times(1)).append(DefaultValueListBoxRenderer.NULL_STR); }
@Test public void testRenderNullWithoutOptions() throws Exception { renderer.render(null, appendable); verify(renderer, times(1)).render(null); verify(appendable, times(1)).append(DefaultValueListBoxRenderer.NULL_STR); }