public List<String> getKeys() {
    return CommonsConfigurationUtils.getKeys(_configuration);
  }
@Test
  public void assertGetKeys() {
    Map<String, Object> properties = new HashMap<>();
    properties.put("property.1.key", "val1");
    properties.put("property.2.key", "val1");
    properties.put("property.3.key", "val1");
    properties.put("property.4.key", "val1");

    PinotConfiguration pinotConfiguration = new PinotConfiguration(properties, new HashMap<>());

    List<String> keys = pinotConfiguration.getKeys();
    Assert.assertTrue(keys.contains("property.1.key"));
    Assert.assertTrue(keys.contains("property.2.key"));
    Assert.assertTrue(keys.contains("property.3.key"));
    Assert.assertTrue(keys.contains("property.4.key"));
    Assert.assertEquals(keys.size(), 4);
  }