@Test
  protected void equality() {
    values(string.value.is("")).isEmpty();
    values(string.value.isNot("")).isEmpty();
    repository.insert(generator.get().withValue("a"));
    repository.insert(generator.get().withValue("bb"));
    repository.insert(generator.get().withValue("ccc"));

    values(string.value.is("a")).hasContentInAnyOrder("a");
    values(string.value.is("bb")).hasContentInAnyOrder("bb");
    values(string.value.isNot("bb")).hasContentInAnyOrder("a", "ccc");
    values(string.value.isNot("a")).hasContentInAnyOrder("bb", "ccc");
    values(string.value.in("a", "bb", "ccc")).hasContentInAnyOrder("a", "bb", "ccc");
    values(string.value.in("a", "bb")).hasContentInAnyOrder("a", "bb");
    values(string.value.notIn("a", "bb", "ccc")).isEmpty();
  }
Testing various string operations prefix/suffix/length etc.
criteria/common/test/org/immutables/criteria/typemodel/StringTemplate.java