are working on. And as mentioned above, API changes should be discussed
thoroughly before moving to code.

Some examples of types of pull requests that are immediately helpful:

  - Fixing a bug without changing a public API.
  - Fixing or improving documentation.
  - Improvements to Maven configuration.

Guidelines for any code contributions:

  1. Any significant changes should be accompanied by tests. The project already

  }

  /**
   * Returns a string containing the string representation of each of {@code parts}, using the
   * previously configured separator between each.
   */
  public final String join(Iterable<? extends @Nullable Object> parts) {
    return join(parts.iterator());
  }

  /**
   * Returns a string containing the string representation of each of {@code parts}, using the

  @Override
  public final void tearDown() {
    try {
      sloppyTearDown();
    } catch (Throwable t) {
      logger.log(Level.INFO, "exception thrown during tearDown: " + t.getMessage(), t);
    }
  }

  public abstract void sloppyTearDown() throws Exception;

   *     annotation type, rather than an interface
   */
  <T> T newProxy(T target, Class<T> interfaceType, long timeoutDuration, TimeUnit timeoutUnit);

  /**
   * Invokes a specified Callable, timing out after the specified time limit. If the target method
   * call finishes before the limit is reached, the return value or a wrapped exception is

   *     arbitrary past or present time
   */
  abstract long reserveEarliestAvailable(int permits, long nowMicros);

  @Override
  public String toString() {
    return String.format(Locale.ROOT, "RateLimiter[stableRate=%3.1fqps]", getRate());
  }

  abstract static class SleepingStopwatch {
    /** Constructor for use by subclasses. */
    protected SleepingStopwatch() {}

   * fallback}. {@link Function#apply} is not invoked until the primary input has failed, so if the
   * primary input succeeds, it is never invoked. If, during the invocation of {@code fallback}, an
   * exception is thrown, this exception is used as the result of the output {@code Future}.
   *
   * <p>Usage example:
   *
   * <pre>{@code

    }
  }

  public static final String TEST_STRING = "a test string";

  public static class StringTask implements Callable<String> {
    @Override
    public String call() {
      return TEST_STRING;
    }
  }

  public Callable<String> latchAwaitingStringTask(final CountDownLatch latch) {
    return new CheckedCallable<String>() {
      @Override
      protected String realCall() {

  public void forTree_acceptsDirectedGraph() throws Exception {
    MutableGraph<String> graph = GraphBuilder.directed().build();
    graph.putEdge("a", "b");

    Traverser.forTree(graph); // Does not throw
  }

  @Test
  public void forTree_withUndirectedGraph_throws() throws Exception {
    MutableGraph<String> graph = GraphBuilder.undirected().build();
    graph.putEdge("a", "b");

    Set<String> set = of("a", "b", "c", "d", "e", "f", "g", "h");
    assertEquals(Sets.newHashSet("a", "b", "c", "d", "e", "f", "g", "h"), set);
  }

  public void testCopyOf_emptyArray() {
    String[] array = new String[0];
    Set<String> set = copyOf(array);
    assertEquals(Collections.<String>emptySet(), set);
    assertSame(this.<String>of(), set);
  }

  public void testCopyOf_arrayOfOneElement() {

    Set<String> set = of("a", "b", "c", "d", "e", "f", "g", "h");
    assertEquals(Sets.newHashSet("a", "b", "c", "d", "e", "f", "g", "h"), set);
  }

  public void testCopyOf_emptyArray() {
    String[] array = new String[0];
    Set<String> set = copyOf(array);
    assertEquals(Collections.<String>emptySet(), set);
    assertSame(this.<String>of(), set);
  }

  public void testCopyOf_arrayOfOneElement() {