} catch (IllegalArgumentException e) {
      // pass
    }
    assertEquals("<lo><hi>", charEscaper.escape("\uDC00\uD800"));
    try {
      unicodeEscaper.escape("\uDC00\uD800");
      fail("should have failed for bad Unicode input");
    } catch (IllegalArgumentException e) {
      // pass
    }
  }

  // A trivial non-optimized escaper for testing.

        minThresholdPosition = pivotNewIndex;
      } else {
        break;
      }
      iterations++;
      if (iterations >= maxIterations) {
        @SuppressWarnings("nullness") // safe because we pass sort() a range that contains real Ts
        T[] castBuffer = (T[]) buffer;
        // We've already taken O(k log k), let's make sure we don't take longer than O(k log k).

   * ImmutableSortedMultiset}, not this dummy version.
   *
   * @throws UnsupportedOperationException always
   * @deprecated <b>Pass a parameter of type {@code Comparable} to use {@link
   *     ImmutableSortedMultiset#of(Comparable)}.</b>
   */
  @DoNotCall("Elements must be Comparable. (Or, pass a Comparator to orderedBy or copyOf.)")
  @Deprecated
  public static <E> ImmutableSortedMultiset<E> of(E element) {

  }

  /**
   * Wrapper for {@link Map#get(Object)} that forces the caller to pass in a key of the same type as
   * the map. Besides being slightly shorter than code that uses {@link #getMap()}, it also ensures
   * that callers don't pass an {@link Entry} by mistake.
   */
  protected V get(K key) {
    return getMap().get(key);
  }

  protected final K k0() {

      fail("Trailing high surrogate should cause exception");
    } catch (IllegalArgumentException expected) {
      // Pass
    }
    try {
      escapeAsString(SIMPLE_ESCAPER, test);
      fail("Trailing high surrogate should cause exception");
    } catch (IllegalArgumentException expected) {
      // Pass
    }
  }

  public void testNullInput() {
    UnicodeEscaper e = SIMPLE_ESCAPER;
    try {

      fail("expected <" + e.getMessage() + "> to contain <" + message + ">");
    }
  }

  /**
   * Test class with valid equals and hashCode methods. Testers created with instances of this class
   * should always pass.
   */
  private static class ValidTestObject {
    private int aspect1;
    private int aspect2;

    ValidTestObject(int aspect1, int aspect2) {
      this.aspect1 = aspect1;
      this.aspect2 = aspect2;

   *
   * <p>This method is declared to accept any 2 {@code Comparable} objects, even if they are not <a
   * href="https://docs.oracle.com/javase/tutorial/collections/interfaces/order.html">mutually
   * comparable</a>. If you pass objects that are not mutually comparable, this method may throw an
   * exception. (The reason for this decision is lost to time, but the reason <i>might</i> be that

    // URL escapers should throw null pointer exceptions for null input
    try {
      e.escape((String) null);
      fail("Escaping null string should throw exception");
    } catch (NullPointerException x) {
      // pass
    }

    // All URL escapers should leave 0-9, A-Z, a-z unescaped
    assertUnescaped(e, 'a');
    assertUnescaped(e, 'z');
    assertUnescaped(e, 'A');
    assertUnescaped(e, 'Z');
    assertUnescaped(e, '0');

 *       the {@code Converter} type using a mocking framework.
 *   <li>Extend this class and implement its {@link #doForward} and {@link #doBackward} methods.
 *   <li><b>Java 8+ users:</b> you may prefer to pass two lambda expressions or method references to
 *       the {@link #from from} factory method.
 * </ul>
 *
 * <p>Using a converter:
 *
 * <ul>

  public void testBadArguments_null() {
    try {
      new PercentEscaper(null, false);
      fail("Expected null pointer exception for null parameter");
    } catch (NullPointerException expected) {
      // pass
    }
  }

  /**
   * Tests that specifying any alphanumeric characters as 'safe' causes an {@link
   * IllegalArgumentException}.
   */
  public void testBadArguments_badchars() {
    String msg =