@Test
public void nullValueIsAccepted() throws Exception {

  try (KafkaStore<String, String> store = new KafkaStore<>(CLUSTER.bootstrapServers(), SERIALIZER, TOPIC)) {
    store.put("key", null);
    assertThat(store.get("key"), is(nullValue()));
    assertThat(store.containsKey("key"), is(true));
  }
}