ToString { public static PTransform<PCollection<?>, PCollection<String>> elements() { return new Elements(); } private  ToString(); static PTransform<PCollection<?>, PCollection<String>> elements(); static PTransform<PCollection<? extends KV<?, ?>>, PCollection<String>> kvs(); static PTransform<PCollection<? extends KV<?, ?>>, PCollection<String>> kvs(
      String delimiter); static PTransform<PCollection<? extends Iterable<?>>, PCollection<String>> iterables(); static PTransform<PCollection<? extends Iterable<?>>, PCollection<String>> iterables(
      String delimiter);  }
@Test @Category(NeedsRunner.class) public void testToStringOf() { Integer[] ints = {1, 2, 3, 4, 5}; String[] strings = {"1", "2", "3", "4", "5"}; PCollection<Integer> input = p.apply(Create.of(Arrays.asList(ints))); PCollection<String> output = input.apply(ToString.elements()); PAssert.that(output).containsInAnyOrder(strings); p.run(); }