@Test
public void testOnOperationCompletion() {

  OperationAccountant underTest = new OperationAccountant();
  SettableApiFuture<String> future = SettableApiFuture.create();
  underTest.registerOperation(future);
  assertTrue(underTest.hasInflightOperations());
  future.set("");
  assertFalse(underTest.hasInflightOperations());
}