### Question:
GroupIdHandler implements CliOptionHandler { @Override public void handle(String optionValue, Options options) { if (StringUtils.isNotBlank(optionValue)) { options.setGroupId(optionValue); } }  @Override void handle(String optionValue, Options options); @Override CliOption getHandledCliOption(); @Override String getHelpMessage();  }### Answer:
@Test public void testHandleWorks() { String propertyValue = "something"; Options options = new Options(); underTest.handle(propertyValue, options); assertThat(options).extracting(Options::getGroupId).isEqualTo(propertyValue); }
@Test public void testHandleDoesNotDoAnythingIfPropertyIsNull() { String propertyValue = null; Options options = new Options(); underTest.handle(propertyValue, options); assertThat(options).extracting(Options::getGroupId).isNull(); }
@Test public void testHandleDoesNotDoAnythingIfPropertyIsEmpty() { String propertyValue = ""; Options options = new Options(); underTest.handle(propertyValue, options); assertThat(options).extracting(Options::getGroupId).isNull(); }
@Test public void testHandleDoesNotDoAnythingIfPropertyIsBlank() { String propertyValue = " "; Options options = new Options(); underTest.handle(propertyValue, options); assertThat(options).extracting(Options::getGroupId).isNull(); }