};
  }

  // catchingAsync tests cloned from the old withFallback tests:

  public void testCatchingAsync_inputDoesNotRaiseException() throws Exception {
    AsyncFunction<Throwable, Integer> fallback = unexpectedAsyncFunction();
    ListenableFuture<Integer> originalFuture = immediateFuture(7);
    ListenableFuture<Integer> faultTolerantFuture =

    };
  }

  // catchingAsync tests cloned from the old withFallback tests:

  public void testCatchingAsync_inputDoesNotRaiseException() throws Exception {
    AsyncFunction<Throwable, Integer> fallback = unexpectedAsyncFunction();
    ListenableFuture<Integer> originalFuture = immediateFuture(7);
    ListenableFuture<Integer> faultTolerantFuture =

  }

  public void testCatchingAsync() throws Exception {
    FluentFuture<?> f =
        FluentFuture.from(immediateFailedFuture(new CustomRuntimeException()))
            .catchingAsync(Throwable.class, t -> immediateFuture(t.getClass()), directExecutor());
    assertThat(f.get()).isEqualTo(CustomRuntimeException.class);
  }

  public void testTransform() throws Exception {
    FluentFuture<Integer> f =

  }

  public void testCatchingAsync() throws Exception {
    FluentFuture<?> f =
        FluentFuture.from(immediateFailedFuture(new CustomRuntimeException()))
            .catchingAsync(Throwable.class, t -> immediateFuture(t.getClass()), directExecutor());
    assertThat(f.get()).isEqualTo(CustomRuntimeException.class);
  }

  public void testTransform() throws Exception {
    FluentFuture<Integer> f =

          @Override
          public String toString() {
            return fallback.toString();
          }
        };
    // TODO(dpb): Switch to future.catchingSync when that exists (passing a throwing function).
    return derive(state.future.catchingAsync(exceptionType, applyFallback, executor));
  }

  /**
   * Returns a new {@code ClosingFuture} pipeline step derived from this one by applying a function

   *
   * // Falling back to a zero counter in case an exception happens when
   * // processing the RPC to fetch counters.
   * ListenableFuture<Integer> faultTolerantFuture = Futures.catchingAsync(
   *     fetchCounterFuture, FetchException.class, x -> immediateFuture(0), directExecutor());
   * }
   *
   * <p>The fallback can also choose to propagate the original exception when desired:
   *

  }

  public void testCatchingAsync_preventsFurtherOperations() {
    ClosingFuture<String> closingFuture = ClosingFuture.from(immediateFuture("value1"));
    ClosingFuture<String> unused =
        closingFuture.catchingAsync(
            Exception.class, withoutCloser(x -> immediateFuture("value2")), executor);
    assertDerivingThrowsIllegalStateException(closingFuture);
    assertFinalStepThrowsIllegalStateException(closingFuture);
  }

  }

  public void testCatchingAsync_preventsFurtherOperations() {
    ClosingFuture<String> closingFuture = ClosingFuture.from(immediateFuture("value1"));
    ClosingFuture<String> unused =
        closingFuture.catchingAsync(
            Exception.class, withoutCloser(x -> immediateFuture("value2")), executor);
    assertDerivingThrowsIllegalStateException(closingFuture);
    assertFinalStepThrowsIllegalStateException(closingFuture);
  }