},
            directExecutor());
    try {
      getDone(chainedFuture);
      fail();
    } catch (ExecutionException expected) {
      NullPointerException cause = (NullPointerException) expected.getCause();
      assertThat(cause)
          .hasMessageThat()
          .contains(
              "AsyncFunction.apply returned null instead of a Future. "

            },
            directExecutor());
    try {
      getDone(chainedFuture);
      fail();
    } catch (ExecutionException expected) {
      NullPointerException cause = (NullPointerException) expected.getCause();
      assertThat(cause)
          .hasMessageThat()
          .contains(
              "AsyncFunction.apply returned null instead of a Future. "

   * successful, and this step has not started when {@code cancel} is called, this step should never
   * run.
   *
   * <p>If successful, causes the objects captured by this step (if already started) and its input
   * step(s) for later closing to be closed on their respective {@link Executor}s. If any such calls

        return lockedGetOrLoad(key, hash, loader);
      } catch (ExecutionException ee) {
        Throwable cause = ee.getCause();
        if (cause instanceof Error) {
          throw new ExecutionError((Error) cause);
        } else if (cause instanceof RuntimeException) {
          throw new UncheckedExecutionException(cause);
        }
        throw ee;
      } finally {
        postReadCleanup();
      }
    }

   * successful, and this step has not started when {@code cancel} is called, this step should never
   * run.
   *
   * <p>If successful, causes the objects captured by this step (if already started) and its input
   * step(s) for later closing to be closed on their respective {@link Executor}s. If any such calls