*       unnecessary; for example, {@code copyOf(copyOf(anArrayList))} should copy the data only
 *       once. This reduces the expense of habitually making defensive copies at API boundaries.
 *       However, the precise conditions for skipping the copy operation are undefined.
 *   <li><b>Warning:</b> a view collection such as {@link ImmutableMap#keySet} or {@link

 * {@link PriorityQueue} and supplies blocking retrieval operations. While this queue is logically
 * unbounded, attempted additions may fail due to resource exhaustion (causing {@code
 * OutOfMemoryError}). This class does not permit {@code null} elements. A priority queue relying on
 * {@linkplain Comparable natural ordering} also does not permit insertion of non-comparable objects

   */
  public final <S extends @Nullable T> Equivalence<Iterable<S>> pairwise() {
    // Ideally, the returned equivalence would support Iterable<? extends T>. However,
    // the need for this is so rare that it's not worth making callers deal with the ugly wildcard.
    return new PairwiseEquivalence<>(this);
  }

  /**
   * Returns a predicate that evaluates to true if and only if the input is equivalent to {@code

 *       unnecessary; for example, {@code copyOf(copyOf(anArrayList))} should copy the data only
 *       once. This reduces the expense of habitually making defensive copies at API boundaries.
 *       However, the precise conditions for skipping the copy operation are undefined.
 *   <li><b>Warning:</b> a view collection such as {@link ImmutableMap#keySet} or {@link

      checkZeroElements(q);
    }
  }

  private void checkZeroElements(BlockingQueue<Object> q) throws InterruptedException {
    for (boolean interruptibly : new boolean[] {true, false}) {
      // asking to drain zero elements
      assertEquals(0, drain(q, ImmutableList.of(), 0, 10, MILLISECONDS, interruptibly));
    }
  }

  public void testEmpty() throws Exception {

   * space in the buffer completely. In general this is a performance problem since the buffer size
   * is permanently reduced, but with certain Reader implementations it could also cause the buffer
   * size to reach 0, causing an infinite loop.
   */
  @SuppressWarnings("InlineMeInliner") // String.repeat unavailable under Java 8
  public void testCopyWithReaderThatDoesNotFillBuffer() throws IOException {

   * space in the buffer completely. In general this is a performance problem since the buffer size
   * is permanently reduced, but with certain Reader implementations it could also cause the buffer
   * size to reach 0, causing an infinite loop.
   */
  @SuppressWarnings("InlineMeInliner") // String.repeat unavailable under Java 8
  public void testCopyWithReaderThatDoesNotFillBuffer() throws IOException {

    }

    @Test
    void testDoFilter_sessionWithoutAuth_shouldChallenge() throws Exception {
        // Initialize filter first
        initializeFilter();

        // Test that having a session but no auth still challenges
        when(request.getHeader("Authorization")).thenReturn(null);
        when(httpSession.getAttribute("NtlmHttpAuth")).thenReturn(null);

      public Iterator<T> iterator() {
        return Iterators.concat(Iterators.transform(inputs.iterator(), Iterable::iterator));
      }
    };
  }

  /** Concatenates a varargs array of iterables without making a defensive copy of the array. */
  private static <T extends @Nullable Object> FluentIterable<T> concatNoDefensiveCopy(
      Iterable<? extends T>... inputs) {
    for (Iterable<? extends T> input : inputs) {

      public Iterator<T> iterator() {
        return Iterators.concat(Iterators.transform(inputs.iterator(), Iterable::iterator));
      }
    };
  }

  /** Concatenates a varargs array of iterables without making a defensive copy of the array. */
  private static <T extends @Nullable Object> FluentIterable<T> concatNoDefensiveCopy(
      Iterable<? extends T>... inputs) {
    for (Iterable<? extends T> input : inputs) {