doTestTrimFrom("x-x-", "x-x");
    doTestTrimFrom("x-xx", "x-xx");
    doTestTrimFrom("x-x--xx---x----x", "x-x--xx---x----x");
    // additional testing using the doc example
    assertThat(anyOf("ab").trimFrom("abacatbab")).isEqualTo("cat");
  }

  private void doTestTrimFrom(String in, String out) {
    // Try a few different matchers which all match '-' and not 'x'
    assertThat(is('-').trimFrom(in)).isEqualTo(out);