}

    /**
     * Associates all of {@code map's} keys and values in the built map. Duplicate keys are not
     * allowed, and will cause {@link #build} to fail.
     *
     * @throws NullPointerException if any key or value in {@code map} is null
     * @throws ClassCastException if any value is not an instance of the type specified by its key
     */
    @CanIgnoreReturnValue

  protected CharEscaper() {}

  /**
   * Returns the escaped form of a given literal string.
   *
   * @param string the literal string to be escaped
   * @return the escaped form of {@code string}
   * @throws NullPointerException if {@code string} is null
   */
  @Override
  public String escape(String string) {
    checkNotNull(string); // GWT specific check (do not optimize)

  public void testRemoveNullValueForbidden() {
    assertThrows(NullPointerException.class, () -> multimap().remove(k0(), null));
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_KEY_QUERIES)
  public void testRemoveNullKeyForbidden() {
    assertThrows(NullPointerException.class, () -> multimap().remove(null, v0()));
    expectUnchanged();
  }

  }

  public void testBuilder_withImmutableEntryAndNullContents() {
    Builder<String, Integer> builder = new Builder<>();
    assertThrows(
        NullPointerException.class, () -> builder.put(immutableEntry("one", (Integer) null)));
    assertThrows(NullPointerException.class, () -> builder.put(immutableEntry((String) null, 1)));
  }

  public void testBuilderWithExpectedKeysNegative() {
    assertThrows(

  public void testRemoveNullValueForbidden() {
    assertThrows(NullPointerException.class, () -> multimap().remove(k0(), null));
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_KEY_QUERIES)
  public void testRemoveNullKeyForbidden() {
    assertThrows(NullPointerException.class, () -> multimap().remove(null, v0()));
    expectUnchanged();
  }

    assertEquals("foo%7Cbar", e.escape("foo%7Cbar")); // idempotent
  }

  /** Test that giving a null 'safeChars' string causes a {@link NullPointerException}. */
  public void testBadArguments_null() {
    assertThrows(NullPointerException.class, () -> new PercentEscaper(null, false));
  }

  /**
   * Tests that specifying any alphanumeric characters as 'safe' causes an {@link

          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)
          .put(NoSuchElementException.class, e -> e instanceof NoSuchElementException)
          .put(NullPointerException.class, e -> e instanceof NullPointerException)
          .put(NumberFormatException.class, e -> e instanceof NumberFormatException)
          .put(RuntimeException.class, e -> e instanceof RuntimeException)

        new WrappedHashMapGenerator() {
          @Override
          Map<String, String> wrap(final HashMap<String, String> map) {
            if (map.containsKey(null)) {
              throw new NullPointerException();
            }
            return new AbstractMap<String, String>() {
              @Override
              public Set<Entry<String, String>> entrySet() {
                return map.entrySet();

    assertSame("x", Strings.padStart("x", -1, '-'));
  }

  // TODO: could remove if we got NPT working in GWT somehow
  public void testPadStart_null() {
    assertThrows(NullPointerException.class, () -> Strings.padStart(null, 5, '0'));
  }

  public void testPadEnd_noPadding() {
    assertSame("", Strings.padEnd("", 0, '-'));
    assertSame("x", Strings.padEnd("x", 0, '-'));

  }

  public void testNewReader() throws IOException {
    File asciiFile = getTestFile("ascii.txt");
    assertThrows(NullPointerException.class, () -> Files.newReader(asciiFile, null));

    assertThrows(NullPointerException.class, () -> Files.newReader(null, UTF_8));

    BufferedReader r = Files.newReader(asciiFile, US_ASCII);
    try {
      assertEquals(ASCII, r.readLine());