@Test
public void adapt_noRow() throws IOException {

  when(mockBigtableResultScanner.next()).thenReturn(null);
  ResultScanner scanner = adapter.adapt(mockBigtableResultScanner, mockSpan);
  assertNull(scanner.next());
  verify(mockBigtableResultScanner).next();
  verifyNoInteractions(mockRowAdapter);
  verify(mockSpan, times(1)).end();
}