@Test
public void apex() throws IOException, SQLException {

  ApexFactory<String> factory = new ApexFactory("a");
  ApexFactory.Apex<String> apex = factory.apex("b");
  ApexFactory.Apex<String> updatedApex = apexUpdaterFactory(factory)
      .updater(apex)
      .appendix("c")
      .done();
  assertThat(apex.concat(), is("ab"));
  assertThat(updatedApex.concat(), is("ac"));
}