public int find(String what) {
    return find(what, 0);
  }
@Test
  public void testFind() throws Exception {
    Text text = new Text("abcd\u20acbdcd\u20ac");
    assertThat(text.find("abd")).isEqualTo(-1);
    assertThat(text.find("ac")).isEqualTo(-1);
    assertThat(text.find("\u20ac")).isEqualTo(4);
    assertThat(text.find("\u20ac", 5)).isEqualTo(11);
  }