assertTrue(source.wasStreamClosed());
  }

  public void testCopyToAppendable_doesNotCloseIfWriter() throws IOException {
    TestWriter writer = new TestWriter();
    assertFalse(writer.closed());
    source.copyTo(writer);
    assertFalse(writer.closed());
  }

  public void testClosesOnErrors_copyingToCharSinkThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, WRITE_THROWS, CLOSE_THROWS)) {

  }

  public void testCreateUnstarted() {
    Stopwatch unstartedStopwatch = Stopwatch.createUnstarted();
    assertFalse(unstartedStopwatch.isRunning());
    assertEquals(0, unstartedStopwatch.elapsed(NANOSECONDS));
  }

  public void testInitialState() {
    assertFalse(stopwatch.isRunning());
    assertEquals(0, stopwatch.elapsed(NANOSECONDS));
  }

  public void testStart() {

  public void testPredicates() throws IOException {
    File asciiFile = getTestFile("ascii.txt");
    File dir = asciiFile.getParentFile();
    assertTrue(Files.isDirectory().apply(dir));
    assertFalse(Files.isFile().apply(dir));

    assertFalse(Files.isDirectory().apply(asciiFile));
    assertTrue(Files.isFile().apply(asciiFile));
  }

  /** Returns a root path for the file system. */
  private static File root() {

    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

    // Start the task to put it in the RUNNING state.  Have to use a separate
    // thread because the task will block on the task latch after unblocking
    // the run latch.
    exec.execute(task);
    runLatch.await();
    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());

    ByteSource fewerBytes = new TestByteSource(newPreFilledByteArray(bytes.length / 2));
    assertFalse(source.contentEquals(fewerBytes));

    byte[] copy = bytes.clone();
    copy[9876] = 1;
    ByteSource oneByteOff = new TestByteSource(copy);
    assertFalse(source.contentEquals(oneByteOff));
  }

  public void testSlice() throws IOException {
    // Test preconditions

  }

  public void testWriteFromStream_doesNotCloseThatStream() throws IOException {
    TestInputStream in = new TestInputStream(new ByteArrayInputStream(new byte[10]));
    assertFalse(in.closed());
    sink.writeFrom(in);
    assertFalse(in.closed());
  }

  public void testClosesOnErrors_copyingFromByteSourceThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, READ_THROWS, CLOSE_THROWS)) {

    RateLimiter limiter = RateLimiter.create(5.0, stopwatch);
    assertTrue(limiter.tryAcquire(0, SECONDS));
    assertFalse(limiter.tryAcquire(0, SECONDS));
    assertFalse(limiter.tryAcquire(0, SECONDS));
    stopwatch.sleepMillis(100);
    assertFalse(limiter.tryAcquire(0, SECONDS));
  }

  public void testTryAcquire_someWaitAllowed() {
    RateLimiter limiter = RateLimiter.create(5.0, stopwatch);

  }

  public void testContainsAll_partialOverlap() {
    assertFalse(
        "containsAll(partialOverlap) should return false",
        collection.containsAll(MinimalCollection.of(e0(), e3())));
  }

  public void testContainsAll_disjoint() {
    assertFalse(
        "containsAll(disjoint) should return false",
        collection.containsAll(MinimalCollection.of(e3())));
  }

    // Later attempts to set the future should return false.
    assertFalse(future.set("x"));
    assertFalse(future.setException(new Exception("bar")));
    assertFalse(future.setFuture(SettableFuture.<String>create()));
    // Check that the future has been set properly.
    assertFalse(future.isDone());
    assertFalse(future.isCancelled());

    // Later attempts to set the future should return false.
    assertFalse(future.set("x"));
    assertFalse(future.setException(new Exception("bar")));
    assertFalse(future.setFuture(SettableFuture.<String>create()));
    // Check that the future has been set properly.
    assertFalse(future.isDone());
    assertFalse(future.isCancelled());