try {
      collection.add(sampleElement);
      fail("add succeeded on unmodifiable collection");
    } catch (UnsupportedOperationException expected) {
    }

    assertCollectionsAreEquivalent(copy, collection);

    try {
      collection.addAll(siblingCollection);
      fail("addAll succeeded on unmodifiable collection");
    } catch (UnsupportedOperationException expected) {
    }

    try {
      collection.add(sampleElement);
      fail("add succeeded on unmodifiable collection");
    } catch (UnsupportedOperationException expected) {
    }

    assertCollectionsAreEquivalent(copy, collection);

    try {
      collection.addAll(siblingCollection);
      fail("addAll succeeded on unmodifiable collection");
    } catch (UnsupportedOperationException expected) {
    }

      if (executed) {
        return;
      }
      executed = true;
      list = runnables;
      runnables = null; // allow GC to free listeners even if this stays around for a while.
    }
    // If we succeeded then list holds all the runnables we to execute. The pairs in the stack are
    // in the opposite order from how they were added so we need to reverse the list to fulfill our
    // contract.

       * other callers have added to it.
       *
       * This read is guaranteed to get us the right value because we only set this once (here).
       *
       * requireNonNull is safe because either our compareAndSet succeeded or it failed because
       * another thread did it for us.
       */
      seenExceptionsLocal = requireNonNull(seenExceptions);
    }
    return seenExceptionsLocal;
  }

          startDraining(true);
          continue DRAINING;
        } else if (result.isUnderflow()) {
          // If encoder underflows, it means either:
          // a) the final flush() succeeded; next drain (then done)
          // b) we encoded all of the input; next flush
          // c) we ran of out input to encode; next read more input
          if (doneEncoding) { // (a)
            doneFlushing = true;

   *     future
   * @param executor Executor to run the function in.
   * @return A future that holds result of the function (if the input succeeded) or the original
   *     input's failure (if not)
   */
  public final <T extends @Nullable Object> FluentFuture<T> transformAsync(
      AsyncFunction<? super V, T> function, Executor executor) {

        boolean expectedSuccess = fitsInInt(expectedResult);
        try {
          assertEquals(b + "^" + k, force32(expectedResult.intValue()), IntMath.checkedPow(b, k));
          assertTrue(b + "^" + k + " should have succeeded", expectedSuccess);
        } catch (ArithmeticException e) {
          assertFalse(b + "^" + k + " should have failed", expectedSuccess);
        }
      }
    }
  }

  @AndroidIncompatible // slow

  public static <V extends @Nullable Object> V getDone(Future<V> future) throws ExecutionException {
    /*
     * We throw IllegalStateException, since the call could succeed later. Perhaps we "should" throw
     * IllegalArgumentException, since the call could succeed with a different argument. Those
     * exceptions' docs suggest that either is acceptable. Google's Java Practices page recommends

      if (result == CancellationException.class) {
        assertTrue(future.isCancelled());
        if (future.wasInterrupted()) {
          // We were cancelled, it is possible that setFuture could have succeeded too.
          assertThat(numSuccessfulSetCalls.get()).isIn(Range.closed(1, 2));
        } else {
          assertThat(numSuccessfulSetCalls.get()).isEqualTo(1);
        }
      } else {

        boolean expectedSuccess = fitsInInt(expectedResult);
        try {
          assertEquals(b + "^" + k, force32(expectedResult.intValue()), IntMath.checkedPow(b, k));
          assertTrue(b + "^" + k + " should have succeeded", expectedSuccess);
        } catch (ArithmeticException e) {
          assertFalse(b + "^" + k + " should have failed", expectedSuccess);
        }
      }
    }
  }

  @AndroidIncompatible // slow