@Test
  public void should_create_given_directory() throws Exception {

    visitor.preVisitDirectory(source.toPath().resolve("widgets"), null);

    assertThat(exists(destination.toPath().resolve("widgets"))).isTrue();
  }
  @Test
  public void should_copy_given_file_from_source_directory() throws Exception {
    write(source.toPath().resolve("pbButton.json"), "contents".getBytes());

    visitor.visitFile(source.toPath().resolve("pbButton.json"), null);

    assertThat(readAllBytes(destination.toPath().resolve("pbButton.json")))
        .isEqualTo("contents".getBytes());
  }