@Test
public void testAddFailure() {

  RuntimeException exception = new RuntimeException("can not perform mutation");
  SettableApiFuture<Void> future = SettableApiFuture.create();
  when(batcher.add(rowMutation)).thenReturn(future);
  future.setException(exception);
  try {
    bulkMutationWrapper.add(rowMutation).get();
    fail("should throw an exception");
  } catch (Exception actualException) {
    assertEquals(exception, actualException.getCause());
  }
  verify(batcher).add(rowMutation);
}