// Two differing invalid pairs.
    assertThat(Strings.commonPrefix("abc\uD8AB\uD8ABdef", "abc\uD8AB\uD8ACxyz"))
        .isEqualTo("abc\uD8AB");
    // One orphan high surrogate.
    assertThat(Strings.commonPrefix("\uD8AB\uDCAB", "\uD8AB")).isEqualTo("");
    // Two orphan high surrogates.
    assertThat(Strings.commonPrefix("\uD8AB", "\uD8AB")).isEqualTo("\uD8AB");
  }

    // Two differing invalid pairs.
    assertThat(Strings.commonPrefix("abc\uD8AB\uD8ABdef", "abc\uD8AB\uD8ACxyz"))
        .isEqualTo("abc\uD8AB");
    // One orphan high surrogate.
    assertThat(Strings.commonPrefix("\uD8AB\uDCAB", "\uD8AB")).isEqualTo("");
    // Two orphan high surrogates.
    assertThat(Strings.commonPrefix("\uD8AB", "\uD8AB")).isEqualTo("\uD8AB");
  }

        assertTrue("Should have at least 2 indices before cleanup", beforeRemove.getIndices().length >= 2);

        // Remove orphaned indices
        suggester.removeDisableIndices();

        // After cleanup
        GetIndexResponse afterRemove = runner.admin().indices().prepareGetIndex().addIndices(getIndexName() + "*").execute().actionGet();