@Test
public void testDownsampleTransformMetricIsAllNull() {

    Transform downsampleTransform = new DownsampleTransform();
    Map<Long, Double> datapoints = new HashMap<Long, Double>();
    Metric metric = new Metric(TEST_SCOPE + "1", TEST_METRIC);
    metric.setDatapoints(datapoints);
    List<Metric> metrics = new ArrayList<Metric>();
    metrics.add(metric);
    List<String> constants = new ArrayList<String>();
    constants.add("3s-count");
    Map<Long, Double> expected = new HashMap<Long, Double>();
    List<Metric> result = downsampleTransform.transform(null, metrics, constants);
    assertEquals(result.size(), 1);
    assertEquals(expected, result.get(0).getDatapoints());
}