@Test
public void testGetNameOwner() {

  // given
  final AccountOperation mockOperation = mock(AccountOperation.class);
  when(mockOperation.getNameOwner(any(Name.class)))
      .thenReturn(AccountAddress.EMPTY);
  final AergoClient mockClient = mock(AergoClient.class);
  when(mockClient.getAccountOperation()).thenReturn(mockOperation);
  final ClientProvider mockClientProvider = mock(ClientProvider.class);
  when(mockClientProvider.getClient()).thenReturn(mockClient);
  // then
  final QueryApi queryApi = new QueryApiImpl(mockClientProvider);
  assertNotNull(queryApi.getNameOwner(randomUUID().toString()));
  assertNotNull(queryApi.getNameOwner(anyName));
}