public void registerStrategy(BatchingStrategy<?, ?, ?> strategy) {
    _strategies.add(strategy);
  }
@Test
  public void testNothingToDoForStrategy() {
    RecordingStrategy<Integer, Integer, String> strategy =
        new RecordingStrategy<>((key, promise) -> promise.done(String.valueOf(key)), key -> 0);

    _batchingSupport.registerStrategy(strategy);

    Task<String> task = Task.par(Task.value("0"), Task.value("1"))
        .map("concat", (s0, s1) -> s0 + s1);

    String result = runAndWait("TestBatchingSupport.testNothingToDoForStrategy", task);

    assertEquals(result, "01");
    assertEquals(strategy.getClassifiedKeys().size(), 0);
    assertEquals(strategy.getExecutedBatches().size(), 0);
    assertEquals(strategy.getExecutedSingletons().size(), 0);
  }