}

  public void testGetOnlyElement_withDefault_empty_null() {
    Iterator<String> iterator = emptyIterator();
    assertThat(Iterators.<@Nullable String>getOnlyElement(iterator, null)).isNull();
  }

  public void testGetOnlyElement_withDefault_two() {
    Iterator<String> iterator = asList("foo", "bar").iterator();
    IllegalArgumentException expected =

      }
    } catch (Throwable caught) {
      assertThat(caught).isInstanceOf(IOException.class);
    }

    assertTrue(c1.isClosed());
    assertTrue(c2.isClosed());
    assertThat(c3).isNull();

    assertTrue(suppressor.suppressions.isEmpty());
  }

  public void testExceptionThrown_whileClosingLastCloseable() throws IOException {
    Closer closer = new Closer(suppressor);

  @Override
  protected final void tearDown() {
    tearDownStack.runTearDown();
    assertWithMessage("exceptions should not be propagated to uncaught exception handlers")
        .that(thrownByExecutionThread)
        .isNull();
  }

  public void testServiceStartStop() throws Exception {
    WaitOnRunService service = new WaitOnRunService();
    assertFalse(service.startUpCalled);

    service.startAsync().awaitRunning();

  }

  public void testGetOnlyElement_withDefault_empty_null() {
    Iterator<String> iterator = emptyIterator();
    assertThat(Iterators.<@Nullable String>getOnlyElement(iterator, null)).isNull();
  }

  public void testGetOnlyElement_withDefault_two() {
    Iterator<String> iterator = asList("foo", "bar").iterator();
    IllegalArgumentException expected =

      assertThat(urls.get(0).getAuthority()).isNull();
      assertThat(urls.get(0).getPath()).endsWith("/relative/path/to/some.jar");

      assertThat(urls.get(1)).isEqualTo(new URL("file:///absolute/path/to/some.jar"));

      assertThat(urls.get(2).getProtocol()).isEqualTo("file");
      assertThat(urls.get(2).getAuthority()).isNull();

  @Override
  protected final void tearDown() {
    tearDownStack.runTearDown();
    assertWithMessage("exceptions should not be propagated to uncaught exception handlers")
        .that(thrownByExecutionThread)
        .isNull();
  }

  public void testServiceStartStop() throws Exception {
    WaitOnRunService service = new WaitOnRunService();
    assertFalse(service.startUpCalled);

    service.startAsync().awaitRunning();

  }

  /** Checks that #drain() invocations behave correctly for a drained (empty) queue. */
  private void assertDrained(BlockingQueue<Object> q) {
    assertThat(q.peek()).isNull();
    assertInterruptibleDrained(q);
    assertUninterruptibleDrained(q);
  }

  private void assertInterruptibleDrained(BlockingQueue<Object> q) {
    // nothing to drain, thus this should wait doing nothing

    assertThat(ms).containsExactly(null, null, null, "a", "b", "b").inOrder();
    assertEquals(3, ms.count(null));

    SortedSet<@Nullable String> elementSet = ms.elementSet();
    assertThat(elementSet.first()).isNull();
    assertThat(elementSet.last()).isEqualTo("b");
    assertEquals(comparator, elementSet.comparator());
  }

  private static final Comparator<String> DEGENERATE_COMPARATOR =
      new Comparator<String>() {

  }

  public void testStringConverter_nullConversions() {
    assertThat(Shorts.stringConverter().convert(null)).isNull();
    assertThat(Shorts.stringConverter().reverse().convert(null)).isNull();
  }

  public void testStringConverter_reverse() {
    Converter<String, Short> converter = Shorts.stringConverter();

    assertThat(transpose(transpose)).isSameInstanceAs(directedGraph);
    AbstractGraphTest.validateGraph(transpose.asGraph());

    assertThat(transpose.edgeValueOrDefault(N1, N2, null)).isNull();
    for (Integer node : directedGraph.nodes()) {
      assertThat(directedGraph.inDegree(node)).isSameInstanceAs(transpose.outDegree(node));