CancellationException expected = assertThrows(CancellationException.class, () -> future.get());
    assertThat(expected).hasCauseThat().isInstanceOf(IllegalArgumentException.class);
    assertThat(expected).hasCauseThat().hasMessageThat().contains(badFuture.toString());
  }

  private Future<?> newFutureInstance() throws Exception {
    return (Future<?>) settableFutureClass.getMethod("create").invoke(null);
  }

    CancellationException expected = assertThrows(CancellationException.class, () -> future.get());
    assertThat(expected).hasCauseThat().isInstanceOf(IllegalArgumentException.class);
    assertThat(expected).hasCauseThat().hasMessageThat().contains(badFuture.toString());
  }

  private Future<?> newFutureInstance() throws Exception {
    return (Future<?>) settableFutureClass.getMethod("create").invoke(null);
  }

    assume().that(graph.allowsSelfLoops()).isFalse();

    IllegalArgumentException e =
        assertThrows(IllegalArgumentException.class, () -> putEdge(N1, N1));
    assertThat(e).hasMessageThat().contains(ERROR_SELF_LOOP);
  }

  @Test
  public void putEdge_allowsSelfLoops() {
    assume().that(graphIsMutable()).isTrue();
    assume().that(graph.allowsSelfLoops()).isTrue();

    Iterator<String> iterator = asList("one", "two").iterator();
    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> getOnlyElement(iterator));
    assertThat(expected).hasMessageThat().isEqualTo("expected one element but was: <one, two>");
  }

  public void testGetOnlyElement_noDefault_fiveElements() {
    Iterator<String> iterator = asList("one", "two", "three", "four", "five").iterator();

    try {
      tester.testForwarding(interfaceType, wrapperFunction);
    } catch (AssertionFailedError expected) {
      for (String message : expectedMessages) {
        assertThat(expected).hasMessageThat().contains(message);
      }
      return;
    }
    fail("expected failure not reported");
  }

  private class ForwardingRunnable implements Runnable {

    private final Runnable runnable;

    TimeoutException e = assertThrows(TimeoutException.class, () -> testFuture.get(1, NANOSECONDS));
    assertThat(e).hasMessageThat().contains("1 nanoseconds");
    assertThat(e).hasMessageThat().contains("Because this test isn't done");
  }

  public void testToString_completesDuringToString() throws Exception {
    AbstractFuture<Object> testFuture =

      shutdown.set(true);
      while (this.isAlive()) {
        Thread.yield();
      }
    }
  }

  void assertWrapsInterruptedException(RuntimeException e) {
    assertThat(e).hasMessageThat().contains("Unexpected interrupt");
    assertThat(e).hasCauseThat().isInstanceOf(InterruptedException.class);
  }

  public void testAwait_countDownLatch_interrupted() {

    TimeoutException e = assertThrows(TimeoutException.class, () -> testFuture.get(1, NANOSECONDS));
    assertThat(e).hasMessageThat().contains("1 nanoseconds");
    assertThat(e).hasMessageThat().contains("Because this test isn't done");
  }

  public void testToString_completesDuringToString() throws Exception {
    AbstractFuture<Object> testFuture =

          fail("Expected IllegalArgumentException");
        } catch (IllegalArgumentException expected) {
          if (expectedMessage != null) {
            assertThat(expected).hasCauseThat().hasMessageThat().isEqualTo(expectedMessage);
          }
        }
      }
    },
    DECODE_CHECKED {
      @Override
      void assertFailsToDecode(

    assume().that(graph.allowsSelfLoops()).isFalse();

    IllegalArgumentException e =
        assertThrows(IllegalArgumentException.class, () -> putEdge(N1, N1));
    assertThat(e).hasMessageThat().contains(ERROR_SELF_LOOP);
  }

  @Test
  public void putEdge_allowsSelfLoops() {
    assume().that(graphIsMutable()).isTrue();
    assume().that(graph.allowsSelfLoops()).isTrue();