assertEquals(Strings.repeat("ZZ", s.length()), matcher.replaceFrom(s, "ZZ"));
    assertEquals("", matcher.trimFrom(s));
    assertEquals(s.length(), matcher.countIn(s));
  }

  // Kotlin subSequence()/replace() always return new strings, violating expectations of this test
  @J2ktIncompatible
  public void testGeneral() {
    doTestGeneral(is('a'), 'a', 'b');
    doTestGeneral(isNot('a'), 'b', 'a');

    assertEquals(Strings.repeat("ZZ", s.length()), matcher.replaceFrom(s, "ZZ"));
    assertEquals("", matcher.trimFrom(s));
    assertEquals(s.length(), matcher.countIn(s));
  }

  // Kotlin subSequence()/replace() always return new strings, violating expectations of this test
  @J2ktIncompatible
  public void testGeneral() {
    doTestGeneral(is('a'), 'a', 'b');
    doTestGeneral(isNot('a'), 'b', 'a');