public String render(File templateFile) throws IOException {
    String template = FileUtils.readFileToString(templateFile, Charset.defaultCharset());
    return render(template);
  }
@Test
  void testIterate() {
    // given
    K8sSpecTemplate template = new K8sSpecTemplate();
    template.put("dict", ImmutableMap.of(
        "k1", "v1",
        "k2", "v2"
    ));

    // when
    String spec = template.render(
        "{% for key, value in dict.items() %}" +
            "key = {{key}}, value = {{value}}\n" +
            "{% endfor %}"
        );

    // then
    assertEquals(
        "key = k1, value = v1\n" +
        "key = k2, value = v2\n", spec);
  }