@Test
public void testSet() {

    // Check that the key doesn't exist
    Datastore datastore = getService();
    KeyFactory keyFactory = datastore.newKeyFactory().setKind(CACHE_KIND);
    Key datastoreKey = keyFactory.newKey("test");
    Entity entity = datastore.get(datastoreKey);
    assertNull(entity);
    // Let the backend set the key/value
    cache.set("test", "abcd".getBytes());
    // Check that the key/value was correctly set
    entity = datastore.get(datastoreKey);
    assertArrayEquals("abcd".getBytes(), entity.getBlob(CACHE_VALUE_FIELD).toByteArray());
}