@GwtIncompatible // java.util.Random, java.util.BitSet
  public void testSmallCharMatcher() {
    CharMatcher len1 = SmallCharMatcher.from(bitSet("#"), "#");
    CharMatcher len2 = SmallCharMatcher.from(bitSet("ab"), "ab");
    CharMatcher len3 = SmallCharMatcher.from(bitSet("abc"), "abc");
    CharMatcher len4 = SmallCharMatcher.from(bitSet("abcd"), "abcd");
    assertTrue(len1.matches('#'));
    assertFalse(len1.matches('!'));