public static Combine.CombineFn<Boolean, ?, Long> combineFn() {
    return new CountIfFn();
  }
@Test
  public void testCreatesAccumulatorCoder() throws CannotProvideCoderException {
    assertNotNull(
        CountIf.combineFn().getAccumulatorCoder(CoderRegistry.createDefault(), BooleanCoder.of()));
  }