public static <T> Inner<T> create() {
    return new Inner<>();
  }
@Test
  @Category(NeedsRunner.class)
  public void addDuplicateField() {
    Schema schema = Schema.builder().addStringField("field1").build();
    thrown.expect(IllegalArgumentException.class);
    pipeline
        .apply(Create.of(Row.withSchema(schema).addValue("value").build()).withRowSchema(schema))
        .apply(AddFields.<Row>create().field("field1", Schema.FieldType.INT32));
    pipeline.run();
  }