@Test
public void testClose() throws IOException {

  Configuration config = new Configuration(false);
  doNothing().when(mockBulkMutation).close();
  when(mockBulkMutation.add(any(RowMutationEntry.class))).thenReturn(future);
  BigtableBufferedMutator underTest = createMutator(config);
  underTest.mutate(SIMPLE_PUT);
  underTest.close();
  verify(mockBulkMutation).add(any(RowMutationEntry.class));
  verify(mockBulkMutation).close();
}