@Test
public void testGetEmptyClusters() {

  ByteBuffer key = ByteBuffer.wrap(KEY);
  TerrapinGetRequest request = prepareGetRequest();
  RequestOptions options = new RequestOptions();
  options.setSelectionPolicy(SelectionPolicy.PRIMARY_FIRST);
  request.setOptions(options);
  request.setClusterList(ImmutableList.copyOf(new String[]{}));
  TerrapinResponse response = new TerrapinResponse().setResponseMap(ImmutableMap.of(
      key, new TerrapinSingleResponse().setValue(ByteBuffer.wrap("value".getBytes()))));
  when(mockClient1.getMany(eq(FILESET), eq(Sets.newHashSet(key)))).thenReturn(
      Future.value(response));
  when(mockClient2.getManyNoRetries(eq(FILESET), eq(Sets.newHashSet(key)))).thenReturn(
      Future.value(response));
  Try<TerrapinSingleResponse> singleResponseTry = serviceIface.get(request).get(Duration.forever());
  assertTrue(singleResponseTry.isThrow());
  assertEquals(TerrapinGetErrorCode.INVALID_REQUEST,
      ((TerrapinGetException)((Throw)singleResponseTry).e()).getErrorCode());
}