// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::cmp::Ordering::{Equal, Greater, Less};
use std::str::{Utf8Error, from_utf8};

#[test]
fn test_le() {
    assert!("" <= "");
    assert!("" <= "foo");
    assert!("foo" <= "foo");
    assert!("foo" != "bar");
}

#[test]
fn test_len() {
    assert_eq!("".len(), 0);
    assert_eq!("hello world".len(), 11);
    assert_eq!("\x63".len(), 1);
    assert_eq!("\u{a2}".len(), 2);
    assert_eq!("\u{3c0}".len(), 2);
    assert_eq!("\u{2620}".len(), 3);
    assert_eq!("\u{1d11e}".len(), 4);

    assert_eq!("".chars().count(), 0);
    assert_eq!("hello world".chars().count(), 11);
    assert_eq!("\x63".chars().count(), 1);
    assert_eq!("\u{a2}".chars().count(), 1);
    assert_eq!("\u{3c0}".chars().count(), 1);
    assert_eq!("\u{2620}".chars().count(), 1);
    assert_eq!("\u{1d11e}".chars().count(), 1);
    assert_eq!("ประเทศไทย中华Việt Nam".chars().count(), 19);

    assert_eq!("ｈｅｌｌｏ".width(false), 10);
    assert_eq!("ｈｅｌｌｏ".width(true), 10);
    assert_eq!("\0\0\0\0\0".width(false), 0);
    assert_eq!("\0\0\0\0\0".width(true), 0);
    assert_eq!("".width(false), 0);
    assert_eq!("".width(true), 0);
    assert_eq!("\u{2081}\u{2082}\u{2083}\u{2084}".width(false), 4);
    assert_eq!("\u{2081}\u{2082}\u{2083}\u{2084}".width(true), 8);
}

#[test]
fn test_find() {
    assert_eq!("hello".find('l'), Some(2));
    assert_eq!("hello".find(|c:char| c == 'o'), Some(4));
    assert!("hello".find('x').is_none());
    assert!("hello".find(|c:char| c == 'x').is_none());
    assert_eq!("ประเทศไทย中华Việt Nam".find('华'), Some(30));
    assert_eq!("ประเทศไทย中华Việt Nam".find(|c: char| c == '华'), Some(30));
}

#[test]
fn test_rfind() {
    assert_eq!("hello".rfind('l'), Some(3));
    assert_eq!("hello".rfind(|c:char| c == 'o'), Some(4));
    assert!("hello".rfind('x').is_none());
    assert!("hello".rfind(|c:char| c == 'x').is_none());
    assert_eq!("ประเทศไทย中华Việt Nam".rfind('华'), Some(30));
    assert_eq!("ประเทศไทย中华Việt Nam".rfind(|c: char| c == '华'), Some(30));
}

#[test]
fn test_collect() {
    let empty = String::from_str("");
    let s: String = empty.chars().collect();
    assert_eq!(empty, s);
    let data = String::from_str("ประเทศไทย中");
    let s: String = data.chars().collect();
    assert_eq!(data, s);
}

#[test]
fn test_into_bytes() {
    let data = String::from_str("asdf");
    let buf = data.into_bytes();
    assert_eq!(buf, b"asdf");
}

#[test]
fn test_find_str() {
    // byte positions
    assert_eq!("".find(""), Some(0));
    assert!("banana".find("apple pie").is_none());

    let data = "abcabc";
    assert_eq!(data[0..6].find("ab"), Some(0));
    assert_eq!(data[2..6].find("ab"), Some(3 - 2));
    assert!(data[2..4].find("ab").is_none());

    let string = "ประเทศไทย中华Việt Nam";
    let mut data = String::from_str(string);
    data.push_str(string);
    assert!(data.find("ไท华").is_none());
    assert_eq!(data[0..43].find(""), Some(0));
    assert_eq!(data[6..43].find(""), Some(6 - 6));

    assert_eq!(data[0..43].find("ประ"), Some( 0));
    assert_eq!(data[0..43].find("ทศไ"), Some(12));
    assert_eq!(data[0..43].find("ย中"), Some(24));
    assert_eq!(data[0..43].find("iệt"), Some(34));
    assert_eq!(data[0..43].find("Nam"), Some(40));

    assert_eq!(data[43..86].find("ประ"), Some(43 - 43));
    assert_eq!(data[43..86].find("ทศไ"), Some(55 - 43));
    assert_eq!(data[43..86].find("ย中"), Some(67 - 43));
    assert_eq!(data[43..86].find("iệt"), Some(77 - 43));
    assert_eq!(data[43..86].find("Nam"), Some(83 - 43));
}

#[test]
fn test_slice_chars() {
    fn t(a: &str, b: &str, start: usize) {
        assert_eq!(a.slice_chars(start, start + b.chars().count()), b);
    }
    t("", "", 0);
    t("hello", "llo", 2);
    t("hello", "el", 1);
    t("αβλ", "β", 1);
    t("αβλ", "", 3);
    assert_eq!("ะเทศไท", "ประเทศไทย中华Việt Nam".slice_chars(2, 8));
}

fn s(x: &str) -> String { x.to_string() }

macro_rules! test_concat {
    ($expected: expr, $string: expr) => {
        {
            let s: String = $string.concat();
            assert_eq!($expected, s);
        }
    }
}

#[test]
fn test_concat_for_different_types() {
    test_concat!("ab", vec![s("a"), s("b")]);
    test_concat!("ab", vec!["a", "b"]);
    test_concat!("ab", vec!["a", "b"]);
    test_concat!("ab", vec![s("a"), s("b")]);
}

#[test]
fn test_concat_for_different_lengths() {
    let empty: &[&str] = &[];
    test_concat!("", empty);
    test_concat!("a", ["a"]);
    test_concat!("ab", ["a", "b"]);
    test_concat!("abc", ["", "a", "bc"]);
}

macro_rules! test_connect {
    ($expected: expr, $string: expr, $delim: expr) => {
        {
            let s = $string.connect($delim);
            assert_eq!($expected, s);
        }
    }
}

#[test]
fn test_connect_for_different_types() {
    test_connect!("a-b", ["a", "b"], "-");
    let hyphen = "-".to_string();
    test_connect!("a-b", [s("a"), s("b")], &*hyphen);
    test_connect!("a-b", vec!["a", "b"], &*hyphen);
    test_connect!("a-b", &*vec!["a", "b"], "-");
    test_connect!("a-b", vec![s("a"), s("b")], "-");
}

#[test]
fn test_connect_for_different_lengths() {
    let empty: &[&str] = &[];
    test_connect!("", empty, "-");
    test_connect!("a", ["a"], "-");
    test_connect!("a-b", ["a", "b"], "-");
    test_connect!("-a-bc", ["", "a", "bc"], "-");
}

#[test]
fn test_unsafe_slice() {
    assert_eq!("ab", unsafe {"abc".slice_unchecked(0, 2)});
    assert_eq!("bc", unsafe {"abc".slice_unchecked(1, 3)});
    assert_eq!("", unsafe {"abc".slice_unchecked(1, 1)});
    fn a_million_letter_a() -> String {
        let mut i = 0;
        let mut rs = String::new();
        while i < 100000 {
            rs.push_str("aaaaaaaaaa");
            i += 1;
        }
        rs
    }
    fn half_a_million_letter_a() -> String {
        let mut i = 0;
        let mut rs = String::new();
        while i < 100000 {
            rs.push_str("aaaaa");
            i += 1;
        }
        rs
    }
    let letters = a_million_letter_a();
    assert!(half_a_million_letter_a() ==
        unsafe {String::from_str(letters.slice_unchecked(
                                 0,
                                 500000))});
}

#[test]
fn test_starts_with() {
    assert!(("".starts_with("")));
    assert!(("abc".starts_with("")));
    assert!(("abc".starts_with("a")));
    assert!((!"a".starts_with("abc")));
    assert!((!"".starts_with("abc")));
    assert!((!"ödd".starts_with("-")));
    assert!(("ödd".starts_with("öd")));
}

#[test]
fn test_ends_with() {
    assert!(("".ends_with("")));
    assert!(("abc".ends_with("")));
    assert!(("abc".ends_with("c")));
    assert!((!"a".ends_with("abc")));
    assert!((!"".ends_with("abc")));
    assert!((!"ddö".ends_with("-")));
    assert!(("ddö".ends_with("dö")));
}

#[test]
fn test_is_empty() {
    assert!("".is_empty());
    assert!(!"a".is_empty());
}

#[test]
fn test_replace() {
    let a = "a";
    assert_eq!("".replace(a, "b"), String::from_str(""));
    assert_eq!("a".replace(a, "b"), String::from_str("b"));
    assert_eq!("ab".replace(a, "b"), String::from_str("bb"));
    let test = "test";
    assert!(" test test ".replace(test, "toast") ==
        String::from_str(" toast toast "));
    assert_eq!(" test test ".replace(test, ""), String::from_str("   "));
}

#[test]
fn test_replace_2a() {
    let data = "ประเทศไทย中华";
    let repl = "دولة الكويت";

    let a = "ประเ";
    let a2 = "دولة الكويتทศไทย中华";
    assert_eq!(data.replace(a, repl), a2);
}

#[test]
fn test_replace_2b() {
    let data = "ประเทศไทย中华";
    let repl = "دولة الكويت";

    let b = "ะเ";
    let b2 = "ปรدولة الكويتทศไทย中华";
    assert_eq!(data.replace(b, repl), b2);
}

#[test]
fn test_replace_2c() {
    let data = "ประเทศไทย中华";
    let repl = "دولة الكويت";

    let c = "中华";
    let c2 = "ประเทศไทยدولة الكويت";
    assert_eq!(data.replace(c, repl), c2);
}

#[test]
fn test_replace_2d() {
    let data = "ประเทศไทย中华";
    let repl = "دولة الكويت";

    let d = "ไท华";
    assert_eq!(data.replace(d, repl), data);
}

#[test]
fn test_slice() {
    assert_eq!("ab", &"abc"[0..2]);
    assert_eq!("bc", &"abc"[1..3]);
    assert_eq!("", &"abc"[1..1]);
    assert_eq!("\u{65e5}", &"\u{65e5}\u{672c}"[0..3]);

    let data = "ประเทศไทย中华";
    assert_eq!("ป", &data[0..3]);
    assert_eq!("ร", &data[3..6]);
    assert_eq!("", &data[3..3]);
    assert_eq!("华", &data[30..33]);

    fn a_million_letter_x() -> String {
        let mut i = 0;
        let mut rs = String::new();
        while i < 100000 {
            rs.push_str("华华华华华华华华华华");
            i += 1;
        }
        rs
    }
    fn half_a_million_letter_x() -> String {
        let mut i = 0;
        let mut rs = String::new();
        while i < 100000 {
            rs.push_str("华华华华华");
            i += 1;
        }
        rs
    }
    let letters = a_million_letter_x();
    assert!(half_a_million_letter_x() ==
        String::from_str(&letters[0..3 * 500000]));
}

#[test]
fn test_slice_2() {
    let ss = "中华Việt Nam";

    assert_eq!("华", &ss[3..6]);
    assert_eq!("Việt Nam", &ss[6..16]);

    assert_eq!("ab", &"abc"[0..2]);
    assert_eq!("bc", &"abc"[1..3]);
    assert_eq!("", &"abc"[1..1]);

    assert_eq!("中", &ss[0..3]);
    assert_eq!("华V", &ss[3..7]);
    assert_eq!("", &ss[3..3]);
    /*0: 中
      3: 华
      6: V
      7: i
      8: ệ
     11: t
     12:
     13: N
     14: a
     15: m */
}

#[test]
#[should_panic]
fn test_slice_fail() {
    &"中华Việt Nam"[0..2];
}

#[test]
fn test_slice_from() {
    assert_eq!(&"abcd"[0..], "abcd");
    assert_eq!(&"abcd"[2..], "cd");
    assert_eq!(&"abcd"[4..], "");
}
#[test]
fn test_slice_to() {
    assert_eq!(&"abcd"[..0], "");
    assert_eq!(&"abcd"[..2], "ab");
    assert_eq!(&"abcd"[..4], "abcd");
}

#[test]
fn test_trim_left_matches() {
    let v: &[char] = &[];
    assert_eq!(" *** foo *** ".trim_left_matches(v), " *** foo *** ");
    let chars: &[char] = &['*', ' '];
    assert_eq!(" *** foo *** ".trim_left_matches(chars), "foo *** ");
    assert_eq!(" ***  *** ".trim_left_matches(chars), "");
    assert_eq!("foo *** ".trim_left_matches(chars), "foo *** ");

    assert_eq!("11foo1bar11".trim_left_matches('1'), "foo1bar11");
    let chars: &[char] = &['1', '2'];
    assert_eq!("12foo1bar12".trim_left_matches(chars), "foo1bar12");
    assert_eq!("123foo1bar123".trim_left_matches(|c: char| c.is_numeric()), "foo1bar123");
}

#[test]
fn test_trim_right_matches() {
    let v: &[char] = &[];
    assert_eq!(" *** foo *** ".trim_right_matches(v), " *** foo *** ");
    let chars: &[char] = &['*', ' '];
    assert_eq!(" *** foo *** ".trim_right_matches(chars), " *** foo");
    assert_eq!(" ***  *** ".trim_right_matches(chars), "");
    assert_eq!(" *** foo".trim_right_matches(chars), " *** foo");

    assert_eq!("11foo1bar11".trim_right_matches('1'), "11foo1bar");
    let chars: &[char] = &['1', '2'];
    assert_eq!("12foo1bar12".trim_right_matches(chars), "12foo1bar");
    assert_eq!("123foo1bar123".trim_right_matches(|c: char| c.is_numeric()), "123foo1bar");
}

#[test]
fn test_trim_matches() {
    let v: &[char] = &[];
    assert_eq!(" *** foo *** ".trim_matches(v), " *** foo *** ");
    let chars: &[char] = &['*', ' '];
    assert_eq!(" *** foo *** ".trim_matches(chars), "foo");
    assert_eq!(" ***  *** ".trim_matches(chars), "");
    assert_eq!("foo".trim_matches(chars), "foo");

    assert_eq!("11foo1bar11".trim_matches('1'), "foo1bar");
    let chars: &[char] = &['1', '2'];
    assert_eq!("12foo1bar12".trim_matches(chars), "foo1bar");
    assert_eq!("123foo1bar123".trim_matches(|c: char| c.is_numeric()), "foo1bar");
}

#[test]
fn test_trim_left() {
    assert_eq!("".trim_left(), "");
    assert_eq!("a".trim_left(), "a");
    assert_eq!("    ".trim_left(), "");
    assert_eq!("     blah".trim_left(), "blah");
    assert_eq!("   \u{3000}  wut".trim_left(), "wut");
    assert_eq!("hey ".trim_left(), "hey ");
}

#[test]
fn test_trim_right() {
    assert_eq!("".trim_right(), "");
    assert_eq!("a".trim_right(), "a");
    assert_eq!("    ".trim_right(), "");
    assert_eq!("blah     ".trim_right(), "blah");
    assert_eq!("wut   \u{3000}  ".trim_right(), "wut");
    assert_eq!(" hey".trim_right(), " hey");
}

#[test]
fn test_trim() {
    assert_eq!("".trim(), "");
    assert_eq!("a".trim(), "a");
    assert_eq!("    ".trim(), "");
    assert_eq!("    blah     ".trim(), "blah");
    assert_eq!("\nwut   \u{3000}  ".trim(), "wut");
    assert_eq!(" hey dude ".trim(), "hey dude");
}

#[test]
fn test_is_whitespace() {
    assert!("".chars().all(|c| c.is_whitespace()));
    assert!(" ".chars().all(|c| c.is_whitespace()));
    assert!("\u{2009}".chars().all(|c| c.is_whitespace())); // Thin space
    assert!("  \n\t   ".chars().all(|c| c.is_whitespace()));
    assert!(!"   _   ".chars().all(|c| c.is_whitespace()));
}

#[test]
fn test_slice_shift_char() {
    let data = "ประเทศไทย中";
    assert_eq!(data.slice_shift_char(), Some(('ป', "ระเทศไทย中")));
}

#[test]
fn test_slice_shift_char_2() {
    let empty = "";
    assert_eq!(empty.slice_shift_char(), None);
}

#[test]
fn test_is_utf8() {
    // deny overlong encodings
    assert!(from_utf8(&[0xc0, 0x80]).is_err());
    assert!(from_utf8(&[0xc0, 0xae]).is_err());
    assert!(from_utf8(&[0xe0, 0x80, 0x80]).is_err());
    assert!(from_utf8(&[0xe0, 0x80, 0xaf]).is_err());
    assert!(from_utf8(&[0xe0, 0x81, 0x81]).is_err());
    assert!(from_utf8(&[0xf0, 0x82, 0x82, 0xac]).is_err());
    assert!(from_utf8(&[0xf4, 0x90, 0x80, 0x80]).is_err());

    // deny surrogates
    assert!(from_utf8(&[0xED, 0xA0, 0x80]).is_err());
    assert!(from_utf8(&[0xED, 0xBF, 0xBF]).is_err());

    assert!(from_utf8(&[0xC2, 0x80]).is_ok());
    assert!(from_utf8(&[0xDF, 0xBF]).is_ok());
    assert!(from_utf8(&[0xE0, 0xA0, 0x80]).is_ok());
    assert!(from_utf8(&[0xED, 0x9F, 0xBF]).is_ok());
    assert!(from_utf8(&[0xEE, 0x80, 0x80]).is_ok());
    assert!(from_utf8(&[0xEF, 0xBF, 0xBF]).is_ok());
    assert!(from_utf8(&[0xF0, 0x90, 0x80, 0x80]).is_ok());
    assert!(from_utf8(&[0xF4, 0x8F, 0xBF, 0xBF]).is_ok());
}

#[test]
fn test_is_utf16() {
    use unicode::str::is_utf16;

    macro_rules! pos {
        ($($e:expr),*) => { { $(assert!(is_utf16($e));)* } }
    }

    // non-surrogates
    pos!(&[0x0000],
         &[0x0001, 0x0002],
         &[0xD7FF],
         &[0xE000]);

    // surrogate pairs (randomly generated with Python 3's
    // .encode('utf-16be'))
    pos!(&[0xdb54, 0xdf16, 0xd880, 0xdee0, 0xdb6a, 0xdd45],
         &[0xd91f, 0xdeb1, 0xdb31, 0xdd84, 0xd8e2, 0xde14],
         &[0xdb9f, 0xdc26, 0xdb6f, 0xde58, 0xd850, 0xdfae]);

    // mixtures (also random)
    pos!(&[0xd921, 0xdcc2, 0x002d, 0x004d, 0xdb32, 0xdf65],
         &[0xdb45, 0xdd2d, 0x006a, 0xdacd, 0xddfe, 0x0006],
         &[0x0067, 0xd8ff, 0xddb7, 0x000f, 0xd900, 0xdc80]);

    // negative tests
    macro_rules! neg {
        ($($e:expr),*) => { { $(assert!(!is_utf16($e));)* } }
    }

    neg!(
        // surrogate + regular unit
        &[0xdb45, 0x0000],
        // surrogate + lead surrogate
        &[0xd900, 0xd900],
        // unterminated surrogate
        &[0xd8ff],
        // trail surrogate without a lead
        &[0xddb7]);

    // random byte sequences that Python 3's .decode('utf-16be')
    // failed on
    neg!(&[0x5b3d, 0x0141, 0xde9e, 0x8fdc, 0xc6e7],
         &[0xdf5a, 0x82a5, 0x62b9, 0xb447, 0x92f3],
         &[0xda4e, 0x42bc, 0x4462, 0xee98, 0xc2ca],
         &[0xbe00, 0xb04a, 0x6ecb, 0xdd89, 0xe278],
         &[0x0465, 0xab56, 0xdbb6, 0xa893, 0x665e],
         &[0x6b7f, 0x0a19, 0x40f4, 0xa657, 0xdcc5],
         &[0x9b50, 0xda5e, 0x24ec, 0x03ad, 0x6dee],
         &[0x8d17, 0xcaa7, 0xf4ae, 0xdf6e, 0xbed7],
         &[0xdaee, 0x2584, 0x7d30, 0xa626, 0x121a],
         &[0xd956, 0x4b43, 0x7570, 0xccd6, 0x4f4a],
         &[0x9dcf, 0x1b49, 0x4ba5, 0xfce9, 0xdffe],
         &[0x6572, 0xce53, 0xb05a, 0xf6af, 0xdacf],
         &[0x1b90, 0x728c, 0x9906, 0xdb68, 0xf46e],
         &[0x1606, 0xbeca, 0xbe76, 0x860f, 0xdfa5],
         &[0x8b4f, 0xde7a, 0xd220, 0x9fac, 0x2b6f],
         &[0xb8fe, 0xebbe, 0xda32, 0x1a5f, 0x8b8b],
         &[0x934b, 0x8956, 0xc434, 0x1881, 0xddf7],
         &[0x5a95, 0x13fc, 0xf116, 0xd89b, 0x93f9],
         &[0xd640, 0x71f1, 0xdd7d, 0x77eb, 0x1cd8],
         &[0x348b, 0xaef0, 0xdb2c, 0xebf1, 0x1282],
         &[0x50d7, 0xd824, 0x5010, 0xb369, 0x22ea]);
}

#[test]
fn test_as_bytes() {
    // no null
    let v = [
        224, 184, 168, 224, 185, 132, 224, 184, 151, 224, 184, 162, 228,
        184, 173, 229, 141, 142, 86, 105, 225, 187, 135, 116, 32, 78, 97,
        109
    ];
    let b: &[u8] = &[];
    assert_eq!("".as_bytes(), b);
    assert_eq!("abc".as_bytes(), b"abc");
    assert_eq!("ศไทย中华Việt Nam".as_bytes(), v);
}

#[test]
#[should_panic]
fn test_as_bytes_fail() {
    // Don't double free. (I'm not sure if this exercises the
    // original problem code path anymore.)
    let s = String::from_str("");
    let _bytes = s.as_bytes();
    panic!();
}

#[test]
fn test_as_ptr() {
    let buf = "hello".as_ptr();
    unsafe {
        assert_eq!(*buf.offset(0), b'h');
        assert_eq!(*buf.offset(1), b'e');
        assert_eq!(*buf.offset(2), b'l');
        assert_eq!(*buf.offset(3), b'l');
        assert_eq!(*buf.offset(4), b'o');
    }
}

#[test]
fn test_subslice_offset() {
    let a = "kernelsprite";
    let b = &a[7..a.len()];
    let c = &a[0..a.len() - 6];
    assert_eq!(a.subslice_offset(b), 7);
    assert_eq!(a.subslice_offset(c), 0);

    let string = "a\nb\nc";
    let lines: Vec<&str> = string.lines().collect();
    assert_eq!(string.subslice_offset(lines[0]), 0);
    assert_eq!(string.subslice_offset(lines[1]), 2);
    assert_eq!(string.subslice_offset(lines[2]), 4);
}

#[test]
#[should_panic]
fn test_subslice_offset_2() {
    let a = "alchemiter";
    let b = "cruxtruder";
    a.subslice_offset(b);
}

#[test]
fn vec_str_conversions() {
    let s1: String = String::from_str("All mimsy were the borogoves");

    let v: Vec<u8> = s1.as_bytes().to_vec();
    let s2: String = String::from_str(from_utf8(&v).unwrap());
    let mut i = 0;
    let n1 = s1.len();
    let n2 = v.len();
    assert_eq!(n1, n2);
    while i < n1 {
        let a: u8 = s1.as_bytes()[i];
        let b: u8 = s2.as_bytes()[i];
        debug!("{}", a);
        debug!("{}", b);
        assert_eq!(a, b);
        i += 1;
    }
}

#[test]
fn test_contains() {
    assert!("abcde".contains("bcd"));
    assert!("abcde".contains("abcd"));
    assert!("abcde".contains("bcde"));
    assert!("abcde".contains(""));
    assert!("".contains(""));
    assert!(!"abcde".contains("def"));
    assert!(!"".contains("a"));

    let data = "ประเทศไทย中华Việt Nam";
    assert!(data.contains("ประเ"));
    assert!(data.contains("ะเ"));
    assert!(data.contains("中华"));
    assert!(!data.contains("ไท华"));
}

#[test]
fn test_contains_char() {
    assert!("abc".contains('b'));
    assert!("a".contains('a'));
    assert!(!"abc".contains('d'));
    assert!(!"".contains('a'));
}

#[test]
fn test_char_at() {
    let s = "ศไทย中华Việt Nam";
    let v = vec!['ศ','ไ','ท','ย','中','华','V','i','ệ','t',' ','N','a','m'];
    let mut pos = 0;
    for ch in &v {
        assert!(s.char_at(pos) == *ch);
        pos += ch.to_string().len();
    }
}

#[test]
fn test_char_at_reverse() {
    let s = "ศไทย中华Việt Nam";
    let v = vec!['ศ','ไ','ท','ย','中','华','V','i','ệ','t',' ','N','a','m'];
    let mut pos = s.len();
    for ch in v.iter().rev() {
        assert!(s.char_at_reverse(pos) == *ch);
        pos -= ch.to_string().len();
    }
}

#[test]
fn test_escape_unicode() {
    assert_eq!("abc".escape_unicode(),
               String::from_str("\\u{61}\\u{62}\\u{63}"));
    assert_eq!("a c".escape_unicode(),
               String::from_str("\\u{61}\\u{20}\\u{63}"));
    assert_eq!("\r\n\t".escape_unicode(),
               String::from_str("\\u{d}\\u{a}\\u{9}"));
    assert_eq!("'\"\\".escape_unicode(),
               String::from_str("\\u{27}\\u{22}\\u{5c}"));
    assert_eq!("\x00\x01\u{fe}\u{ff}".escape_unicode(),
               String::from_str("\\u{0}\\u{1}\\u{fe}\\u{ff}"));
    assert_eq!("\u{100}\u{ffff}".escape_unicode(),
               String::from_str("\\u{100}\\u{ffff}"));
    assert_eq!("\u{10000}\u{10ffff}".escape_unicode(),
               String::from_str("\\u{10000}\\u{10ffff}"));
    assert_eq!("ab\u{fb00}".escape_unicode(),
               String::from_str("\\u{61}\\u{62}\\u{fb00}"));
    assert_eq!("\u{1d4ea}\r".escape_unicode(),
               String::from_str("\\u{1d4ea}\\u{d}"));
}

#[test]
fn test_escape_default() {
    assert_eq!("abc".escape_default(), String::from_str("abc"));
    assert_eq!("a c".escape_default(), String::from_str("a c"));
    assert_eq!("\r\n\t".escape_default(), String::from_str("\\r\\n\\t"));
    assert_eq!("'\"\\".escape_default(), String::from_str("\\'\\\"\\\\"));
    assert_eq!("\u{100}\u{ffff}".escape_default(),
               String::from_str("\\u{100}\\u{ffff}"));
    assert_eq!("\u{10000}\u{10ffff}".escape_default(),
               String::from_str("\\u{10000}\\u{10ffff}"));
    assert_eq!("ab\u{fb00}".escape_default(),
               String::from_str("ab\\u{fb00}"));
    assert_eq!("\u{1d4ea}\r".escape_default(),
               String::from_str("\\u{1d4ea}\\r"));
}

#[test]
fn test_total_ord() {
    "1234".cmp("123") == Greater;
    "123".cmp("1234") == Less;
    "1234".cmp("1234") == Equal;
    "12345555".cmp("123456") == Less;
    "22".cmp("1234") == Greater;
}

#[test]
fn test_char_range_at() {
    let data = "b¢€𤭢𤭢€¢b";
    assert_eq!('b', data.char_range_at(0).ch);
    assert_eq!('¢', data.char_range_at(1).ch);
    assert_eq!('€', data.char_range_at(3).ch);
    assert_eq!('𤭢', data.char_range_at(6).ch);
    assert_eq!('𤭢', data.char_range_at(10).ch);
    assert_eq!('€', data.char_range_at(14).ch);
    assert_eq!('¢', data.char_range_at(17).ch);
    assert_eq!('b', data.char_range_at(19).ch);
}

#[test]
fn test_char_range_at_reverse_underflow() {
    assert_eq!("abc".char_range_at_reverse(0).next, 0);
}

#[test]
fn test_iterator() {
    let s = "ศไทย中华Việt Nam";
    let v = ['ศ','ไ','ท','ย','中','华','V','i','ệ','t',' ','N','a','m'];

    let mut pos = 0;
    let it = s.chars();

    for c in it {
        assert_eq!(c, v[pos]);
        pos += 1;
    }
    assert_eq!(pos, v.len());
}

#[test]
fn test_rev_iterator() {
    let s = "ศไทย中华Việt Nam";
    let v = ['m', 'a', 'N', ' ', 't', 'ệ','i','V','华','中','ย','ท','ไ','ศ'];

    let mut pos = 0;
    let it = s.chars().rev();

    for c in it {
        assert_eq!(c, v[pos]);
        pos += 1;
    }
    assert_eq!(pos, v.len());
}

#[test]
fn test_chars_decoding() {
    let mut bytes = [0; 4];
    for c in (0..0x110000).filter_map(::std::char::from_u32) {
        let len = c.encode_utf8(&mut bytes).unwrap_or(0);
        let s = ::std::str::from_utf8(&bytes[..len]).unwrap();
        if Some(c) != s.chars().next() {
            panic!("character {:x}={} does not decode correctly", c as u32, c);
        }
    }
}

#[test]
fn test_chars_rev_decoding() {
    let mut bytes = [0; 4];
    for c in (0..0x110000).filter_map(::std::char::from_u32) {
        let len = c.encode_utf8(&mut bytes).unwrap_or(0);
        let s = ::std::str::from_utf8(&bytes[..len]).unwrap();
        if Some(c) != s.chars().rev().next() {
            panic!("character {:x}={} does not decode correctly", c as u32, c);
        }
    }
}

#[test]
fn test_iterator_clone() {
    let s = "ศไทย中华Việt Nam";
    let mut it = s.chars();
    it.next();
    assert!(it.clone().zip(it).all(|(x,y)| x == y));
}

#[test]
fn test_bytesator() {
    let s = "ศไทย中华Việt Nam";
    let v = [
        224, 184, 168, 224, 185, 132, 224, 184, 151, 224, 184, 162, 228,
        184, 173, 229, 141, 142, 86, 105, 225, 187, 135, 116, 32, 78, 97,
        109
    ];
    let mut pos = 0;

    for b in s.bytes() {
        assert_eq!(b, v[pos]);
        pos += 1;
    }
}

#[test]
fn test_bytes_revator() {
    let s = "ศไทย中华Việt Nam";
    let v = [
        224, 184, 168, 224, 185, 132, 224, 184, 151, 224, 184, 162, 228,
        184, 173, 229, 141, 142, 86, 105, 225, 187, 135, 116, 32, 78, 97,
        109
    ];
    let mut pos = v.len();

    for b in s.bytes().rev() {
        pos -= 1;
        assert_eq!(b, v[pos]);
    }
}

#[test]
fn test_char_indicesator() {
    let s = "ศไทย中华Việt Nam";
    let p = [0, 3, 6, 9, 12, 15, 18, 19, 20, 23, 24, 25, 26, 27];
    let v = ['ศ','ไ','ท','ย','中','华','V','i','ệ','t',' ','N','a','m'];

    let mut pos = 0;
    let it = s.char_indices();

    for c in it {
        assert_eq!(c, (p[pos], v[pos]));
        pos += 1;
    }
    assert_eq!(pos, v.len());
    assert_eq!(pos, p.len());
}

#[test]
fn test_char_indices_revator() {
    let s = "ศไทย中华Việt Nam";
    let p = [27, 26, 25, 24, 23, 20, 19, 18, 15, 12, 9, 6, 3, 0];
    let v = ['m', 'a', 'N', ' ', 't', 'ệ','i','V','华','中','ย','ท','ไ','ศ'];

    let mut pos = 0;
    let it = s.char_indices().rev();

    for c in it {
        assert_eq!(c, (p[pos], v[pos]));
        pos += 1;
    }
    assert_eq!(pos, v.len());
    assert_eq!(pos, p.len());
}

#[test]
fn test_splitn_char_iterator() {
    let data = "\nMäry häd ä little lämb\nLittle lämb\n";

    let split: Vec<&str> = data.splitn(4, ' ').collect();
    assert_eq!(split, ["\nMäry", "häd", "ä", "little lämb\nLittle lämb\n"]);

    let split: Vec<&str> = data.splitn(4, |c: char| c == ' ').collect();
    assert_eq!(split, ["\nMäry", "häd", "ä", "little lämb\nLittle lämb\n"]);

    // Unicode
    let split: Vec<&str> = data.splitn(4, 'ä').collect();
    assert_eq!(split, ["\nM", "ry h", "d ", " little lämb\nLittle lämb\n"]);

    let split: Vec<&str> = data.splitn(4, |c: char| c == 'ä').collect();
    assert_eq!(split, ["\nM", "ry h", "d ", " little lämb\nLittle lämb\n"]);
}

#[test]
fn test_split_char_iterator_no_trailing() {
    let data = "\nMäry häd ä little lämb\nLittle lämb\n";

    let split: Vec<&str> = data.split('\n').collect();
    assert_eq!(split, ["", "Märy häd ä little lämb", "Little lämb", ""]);

    let split: Vec<&str> = data.split_terminator('\n').collect();
    assert_eq!(split, ["", "Märy häd ä little lämb", "Little lämb"]);
}

#[test]
fn test_rsplit() {
    let data = "\nMäry häd ä little lämb\nLittle lämb\n";

    let split: Vec<&str> = data.rsplit(' ').collect();
    assert_eq!(split, ["lämb\n", "lämb\nLittle", "little", "ä", "häd", "\nMäry"]);

    let split: Vec<&str> = data.rsplit("lämb").collect();
    assert_eq!(split, ["\n", "\nLittle ", "\nMäry häd ä little "]);

    let split: Vec<&str> = data.rsplit(|c: char| c == 'ä').collect();
    assert_eq!(split, ["mb\n", "mb\nLittle l", " little l", "d ", "ry h", "\nM"]);
}

#[test]
fn test_rsplitn() {
    let data = "\nMäry häd ä little lämb\nLittle lämb\n";

    let split: Vec<&str> = data.rsplitn(2, ' ').collect();
    assert_eq!(split, ["lämb\n", "\nMäry häd ä little lämb\nLittle"]);

    let split: Vec<&str> = data.rsplitn(2, "lämb").collect();
    assert_eq!(split, ["\n", "\nMäry häd ä little lämb\nLittle "]);

    let split: Vec<&str> = data.rsplitn(2, |c: char| c == 'ä').collect();
    assert_eq!(split, ["mb\n", "\nMäry häd ä little lämb\nLittle l"]);
}

#[test]
fn test_words() {
    let data = "\n \tMäry   häd\tä  little lämb\nLittle lämb\n";
    let words: Vec<&str> = data.words().collect();
    assert_eq!(words, ["Märy", "häd", "ä", "little", "lämb", "Little", "lämb"])
}

#[test]
fn test_nfd_chars() {
    macro_rules! t {
        ($input: expr, $expected: expr) => {
            assert_eq!($input.nfd_chars().collect::<String>(), $expected);
        }
    }
    t!("abc", "abc");
    t!("\u{1e0b}\u{1c4}", "d\u{307}\u{1c4}");
    t!("\u{2026}", "\u{2026}");
    t!("\u{2126}", "\u{3a9}");
    t!("\u{1e0b}\u{323}", "d\u{323}\u{307}");
    t!("\u{1e0d}\u{307}", "d\u{323}\u{307}");
    t!("a\u{301}", "a\u{301}");
    t!("\u{301}a", "\u{301}a");
    t!("\u{d4db}", "\u{1111}\u{1171}\u{11b6}");
    t!("\u{ac1c}", "\u{1100}\u{1162}");
}

#[test]
fn test_nfkd_chars() {
    macro_rules! t {
        ($input: expr, $expected: expr) => {
            assert_eq!($input.nfkd_chars().collect::<String>(), $expected);
        }
    }
    t!("abc", "abc");
    t!("\u{1e0b}\u{1c4}", "d\u{307}DZ\u{30c}");
    t!("\u{2026}", "...");
    t!("\u{2126}", "\u{3a9}");
    t!("\u{1e0b}\u{323}", "d\u{323}\u{307}");
    t!("\u{1e0d}\u{307}", "d\u{323}\u{307}");
    t!("a\u{301}", "a\u{301}");
    t!("\u{301}a", "\u{301}a");
    t!("\u{d4db}", "\u{1111}\u{1171}\u{11b6}");
    t!("\u{ac1c}", "\u{1100}\u{1162}");
}

#[test]
fn test_nfc_chars() {
    macro_rules! t {
        ($input: expr, $expected: expr) => {
            assert_eq!($input.nfc_chars().collect::<String>(), $expected);
        }
    }
    t!("abc", "abc");
    t!("\u{1e0b}\u{1c4}", "\u{1e0b}\u{1c4}");
    t!("\u{2026}", "\u{2026}");
    t!("\u{2126}", "\u{3a9}");
    t!("\u{1e0b}\u{323}", "\u{1e0d}\u{307}");
    t!("\u{1e0d}\u{307}", "\u{1e0d}\u{307}");
    t!("a\u{301}", "\u{e1}");
    t!("\u{301}a", "\u{301}a");
    t!("\u{d4db}", "\u{d4db}");
    t!("\u{ac1c}", "\u{ac1c}");
    t!("a\u{300}\u{305}\u{315}\u{5ae}b", "\u{e0}\u{5ae}\u{305}\u{315}b");
}

#[test]
fn test_nfkc_chars() {
    macro_rules! t {
        ($input: expr, $expected: expr) => {
            assert_eq!($input.nfkc_chars().collect::<String>(), $expected);
        }
    }
    t!("abc", "abc");
    t!("\u{1e0b}\u{1c4}", "\u{1e0b}D\u{17d}");
    t!("\u{2026}", "...");
    t!("\u{2126}", "\u{3a9}");
    t!("\u{1e0b}\u{323}", "\u{1e0d}\u{307}");
    t!("\u{1e0d}\u{307}", "\u{1e0d}\u{307}");
    t!("a\u{301}", "\u{e1}");
    t!("\u{301}a", "\u{301}a");
    t!("\u{d4db}", "\u{d4db}");
    t!("\u{ac1c}", "\u{ac1c}");
    t!("a\u{300}\u{305}\u{315}\u{5ae}b", "\u{e0}\u{5ae}\u{305}\u{315}b");
}

#[test]
fn test_lines() {
    let data = "\nMäry häd ä little lämb\n\nLittle lämb\n";
    let lines: Vec<&str> = data.lines().collect();
    assert_eq!(lines, ["", "Märy häd ä little lämb", "", "Little lämb"]);

    let data = "\nMäry häd ä little lämb\n\nLittle lämb"; // no trailing \n
    let lines: Vec<&str> = data.lines().collect();
    assert_eq!(lines, ["", "Märy häd ä little lämb", "", "Little lämb"]);
}

#[test]
fn test_graphemes() {
    use std::iter::order;

    // official Unicode test data
    // from http://www.unicode.org/Public/UCD/latest/ucd/auxiliary/GraphemeBreakTest.txt
    let test_same: [(_, &[_]); 325] = [
        ("\u{20}\u{20}", &["\u{20}", "\u{20}"]),
        ("\u{20}\u{308}\u{20}", &["\u{20}\u{308}", "\u{20}"]),
        ("\u{20}\u{D}", &["\u{20}", "\u{D}"]),
        ("\u{20}\u{308}\u{D}", &["\u{20}\u{308}", "\u{D}"]),
        ("\u{20}\u{A}", &["\u{20}", "\u{A}"]),
        ("\u{20}\u{308}\u{A}", &["\u{20}\u{308}", "\u{A}"]),
        ("\u{20}\u{1}", &["\u{20}", "\u{1}"]),
        ("\u{20}\u{308}\u{1}", &["\u{20}\u{308}", "\u{1}"]),
        ("\u{20}\u{300}", &["\u{20}\u{300}"]),
        ("\u{20}\u{308}\u{300}", &["\u{20}\u{308}\u{300}"]),
        ("\u{20}\u{1100}", &["\u{20}", "\u{1100}"]),
        ("\u{20}\u{308}\u{1100}", &["\u{20}\u{308}", "\u{1100}"]),
        ("\u{20}\u{1160}", &["\u{20}", "\u{1160}"]),
        ("\u{20}\u{308}\u{1160}", &["\u{20}\u{308}", "\u{1160}"]),
        ("\u{20}\u{11A8}", &["\u{20}", "\u{11A8}"]),
        ("\u{20}\u{308}\u{11A8}", &["\u{20}\u{308}", "\u{11A8}"]),
        ("\u{20}\u{AC00}", &["\u{20}", "\u{AC00}"]),
        ("\u{20}\u{308}\u{AC00}", &["\u{20}\u{308}", "\u{AC00}"]),
        ("\u{20}\u{AC01}", &["\u{20}", "\u{AC01}"]),
        ("\u{20}\u{308}\u{AC01}", &["\u{20}\u{308}", "\u{AC01}"]),
        ("\u{20}\u{1F1E6}", &["\u{20}", "\u{1F1E6}"]),
        ("\u{20}\u{308}\u{1F1E6}", &["\u{20}\u{308}", "\u{1F1E6}"]),
        ("\u{20}\u{378}", &["\u{20}", "\u{378}"]),
        ("\u{20}\u{308}\u{378}", &["\u{20}\u{308}", "\u{378}"]),
        ("\u{D}\u{20}", &["\u{D}", "\u{20}"]),
        ("\u{D}\u{308}\u{20}", &["\u{D}", "\u{308}", "\u{20}"]),
        ("\u{D}\u{D}", &["\u{D}", "\u{D}"]),
        ("\u{D}\u{308}\u{D}", &["\u{D}", "\u{308}", "\u{D}"]),
        ("\u{D}\u{A}", &["\u{D}\u{A}"]),
        ("\u{D}\u{308}\u{A}", &["\u{D}", "\u{308}", "\u{A}"]),
        ("\u{D}\u{1}", &["\u{D}", "\u{1}"]),
        ("\u{D}\u{308}\u{1}", &["\u{D}", "\u{308}", "\u{1}"]),
        ("\u{D}\u{300}", &["\u{D}", "\u{300}"]),
        ("\u{D}\u{308}\u{300}", &["\u{D}", "\u{308}\u{300}"]),
        ("\u{D}\u{903}", &["\u{D}", "\u{903}"]),
        ("\u{D}\u{1100}", &["\u{D}", "\u{1100}"]),
        ("\u{D}\u{308}\u{1100}", &["\u{D}", "\u{308}", "\u{1100}"]),
        ("\u{D}\u{1160}", &["\u{D}", "\u{1160}"]),
        ("\u{D}\u{308}\u{1160}", &["\u{D}", "\u{308}", "\u{1160}"]),
        ("\u{D}\u{11A8}", &["\u{D}", "\u{11A8}"]),
        ("\u{D}\u{308}\u{11A8}", &["\u{D}", "\u{308}", "\u{11A8}"]),
        ("\u{D}\u{AC00}", &["\u{D}", "\u{AC00}"]),
        ("\u{D}\u{308}\u{AC00}", &["\u{D}", "\u{308}", "\u{AC00}"]),
        ("\u{D}\u{AC01}", &["\u{D}", "\u{AC01}"]),
        ("\u{D}\u{308}\u{AC01}", &["\u{D}", "\u{308}", "\u{AC01}"]),
        ("\u{D}\u{1F1E6}", &["\u{D}", "\u{1F1E6}"]),
        ("\u{D}\u{308}\u{1F1E6}", &["\u{D}", "\u{308}", "\u{1F1E6}"]),
        ("\u{D}\u{378}", &["\u{D}", "\u{378}"]),
        ("\u{D}\u{308}\u{378}", &["\u{D}", "\u{308}", "\u{378}"]),
        ("\u{A}\u{20}", &["\u{A}", "\u{20}"]),
        ("\u{A}\u{308}\u{20}", &["\u{A}", "\u{308}", "\u{20}"]),
        ("\u{A}\u{D}", &["\u{A}", "\u{D}"]),
        ("\u{A}\u{308}\u{D}", &["\u{A}", "\u{308}", "\u{D}"]),
        ("\u{A}\u{A}", &["\u{A}", "\u{A}"]),
        ("\u{A}\u{308}\u{A}", &["\u{A}", "\u{308}", "\u{A}"]),
        ("\u{A}\u{1}", &["\u{A}", "\u{1}"]),
        ("\u{A}\u{308}\u{1}", &["\u{A}", "\u{308}", "\u{1}"]),
        ("\u{A}\u{300}", &["\u{A}", "\u{300}"]),
        ("\u{A}\u{308}\u{300}", &["\u{A}", "\u{308}\u{300}"]),
        ("\u{A}\u{903}", &["\u{A}", "\u{903}"]),
        ("\u{A}\u{1100}", &["\u{A}", "\u{1100}"]),
        ("\u{A}\u{308}\u{1100}", &["\u{A}", "\u{308}", "\u{1100}"]),
        ("\u{A}\u{1160}", &["\u{A}", "\u{1160}"]),
        ("\u{A}\u{308}\u{1160}", &["\u{A}", "\u{308}", "\u{1160}"]),
        ("\u{A}\u{11A8}", &["\u{A}", "\u{11A8}"]),
        ("\u{A}\u{308}\u{11A8}", &["\u{A}", "\u{308}", "\u{11A8}"]),
        ("\u{A}\u{AC00}", &["\u{A}", "\u{AC00}"]),
        ("\u{A}\u{308}\u{AC00}", &["\u{A}", "\u{308}", "\u{AC00}"]),
        ("\u{A}\u{AC01}", &["\u{A}", "\u{AC01}"]),
        ("\u{A}\u{308}\u{AC01}", &["\u{A}", "\u{308}", "\u{AC01}"]),
        ("\u{A}\u{1F1E6}", &["\u{A}", "\u{1F1E6}"]),
        ("\u{A}\u{308}\u{1F1E6}", &["\u{A}", "\u{308}", "\u{1F1E6}"]),
        ("\u{A}\u{378}", &["\u{A}", "\u{378}"]),
        ("\u{A}\u{308}\u{378}", &["\u{A}", "\u{308}", "\u{378}"]),
        ("\u{1}\u{20}", &["\u{1}", "\u{20}"]),
        ("\u{1}\u{308}\u{20}", &["\u{1}", "\u{308}", "\u{20}"]),
        ("\u{1}\u{D}", &["\u{1}", "\u{D}"]),
        ("\u{1}\u{308}\u{D}", &["\u{1}", "\u{308}", "\u{D}"]),
        ("\u{1}\u{A}", &["\u{1}", "\u{A}"]),
        ("\u{1}\u{308}\u{A}", &["\u{1}", "\u{308}", "\u{A}"]),
        ("\u{1}\u{1}", &["\u{1}", "\u{1}"]),
        ("\u{1}\u{308}\u{1}", &["\u{1}", "\u{308}", "\u{1}"]),
        ("\u{1}\u{300}", &["\u{1}", "\u{300}"]),
        ("\u{1}\u{308}\u{300}", &["\u{1}", "\u{308}\u{300}"]),
        ("\u{1}\u{903}", &["\u{1}", "\u{903}"]),
        ("\u{1}\u{1100}", &["\u{1}", "\u{1100}"]),
        ("\u{1}\u{308}\u{1100}", &["\u{1}", "\u{308}", "\u{1100}"]),
        ("\u{1}\u{1160}", &["\u{1}", "\u{1160}"]),
        ("\u{1}\u{308}\u{1160}", &["\u{1}", "\u{308}", "\u{1160}"]),
        ("\u{1}\u{11A8}", &["\u{1}", "\u{11A8}"]),
        ("\u{1}\u{308}\u{11A8}", &["\u{1}", "\u{308}", "\u{11A8}"]),
        ("\u{1}\u{AC00}", &["\u{1}", "\u{AC00}"]),
        ("\u{1}\u{308}\u{AC00}", &["\u{1}", "\u{308}", "\u{AC00}"]),
        ("\u{1}\u{AC01}", &["\u{1}", "\u{AC01}"]),
        ("\u{1}\u{308}\u{AC01}", &["\u{1}", "\u{308}", "\u{AC01}"]),
        ("\u{1}\u{1F1E6}", &["\u{1}", "\u{1F1E6}"]),
        ("\u{1}\u{308}\u{1F1E6}", &["\u{1}", "\u{308}", "\u{1F1E6}"]),
        ("\u{1}\u{378}", &["\u{1}", "\u{378}"]),
        ("\u{1}\u{308}\u{378}", &["\u{1}", "\u{308}", "\u{378}"]),
        ("\u{300}\u{20}", &["\u{300}", "\u{20}"]),
        ("\u{300}\u{308}\u{20}", &["\u{300}\u{308}", "\u{20}"]),
        ("\u{300}\u{D}", &["\u{300}", "\u{D}"]),
        ("\u{300}\u{308}\u{D}", &["\u{300}\u{308}", "\u{D}"]),
        ("\u{300}\u{A}", &["\u{300}", "\u{A}"]),
        ("\u{300}\u{308}\u{A}", &["\u{300}\u{308}", "\u{A}"]),
        ("\u{300}\u{1}", &["\u{300}", "\u{1}"]),
        ("\u{300}\u{308}\u{1}", &["\u{300}\u{308}", "\u{1}"]),
        ("\u{300}\u{300}", &["\u{300}\u{300}"]),
        ("\u{300}\u{308}\u{300}", &["\u{300}\u{308}\u{300}"]),
        ("\u{300}\u{1100}", &["\u{300}", "\u{1100}"]),
        ("\u{300}\u{308}\u{1100}", &["\u{300}\u{308}", "\u{1100}"]),
        ("\u{300}\u{1160}", &["\u{300}", "\u{1160}"]),
        ("\u{300}\u{308}\u{1160}", &["\u{300}\u{308}", "\u{1160}"]),
        ("\u{300}\u{11A8}", &["\u{300}", "\u{11A8}"]),
        ("\u{300}\u{308}\u{11A8}", &["\u{300}\u{308}", "\u{11A8}"]),
        ("\u{300}\u{AC00}", &["\u{300}", "\u{AC00}"]),
        ("\u{300}\u{308}\u{AC00}", &["\u{300}\u{308}", "\u{AC00}"]),
        ("\u{300}\u{AC01}", &["\u{300}", "\u{AC01}"]),
        ("\u{300}\u{308}\u{AC01}", &["\u{300}\u{308}", "\u{AC01}"]),
        ("\u{300}\u{1F1E6}", &["\u{300}", "\u{1F1E6}"]),
        ("\u{300}\u{308}\u{1F1E6}", &["\u{300}\u{308}", "\u{1F1E6}"]),
        ("\u{300}\u{378}", &["\u{300}", "\u{378}"]),
        ("\u{300}\u{308}\u{378}", &["\u{300}\u{308}", "\u{378}"]),
        ("\u{903}\u{20}", &["\u{903}", "\u{20}"]),
        ("\u{903}\u{308}\u{20}", &["\u{903}\u{308}", "\u{20}"]),
        ("\u{903}\u{D}", &["\u{903}", "\u{D}"]),
        ("\u{903}\u{308}\u{D}", &["\u{903}\u{308}", "\u{D}"]),
        ("\u{903}\u{A}", &["\u{903}", "\u{A}"]),
        ("\u{903}\u{308}\u{A}", &["\u{903}\u{308}", "\u{A}"]),
        ("\u{903}\u{1}", &["\u{903}", "\u{1}"]),
        ("\u{903}\u{308}\u{1}", &["\u{903}\u{308}", "\u{1}"]),
        ("\u{903}\u{300}", &["\u{903}\u{300}"]),
        ("\u{903}\u{308}\u{300}", &["\u{903}\u{308}\u{300}"]),
        ("\u{903}\u{1100}", &["\u{903}", "\u{1100}"]),
        ("\u{903}\u{308}\u{1100}", &["\u{903}\u{308}", "\u{1100}"]),
        ("\u{903}\u{1160}", &["\u{903}", "\u{1160}"]),
        ("\u{903}\u{308}\u{1160}", &["\u{903}\u{308}", "\u{1160}"]),
        ("\u{903}\u{11A8}", &["\u{903}", "\u{11A8}"]),
        ("\u{903}\u{308}\u{11A8}", &["\u{903}\u{308}", "\u{11A8}"]),
        ("\u{903}\u{AC00}", &["\u{903}", "\u{AC00}"]),
        ("\u{903}\u{308}\u{AC00}", &["\u{903}\u{308}", "\u{AC00}"]),
        ("\u{903}\u{AC01}", &["\u{903}", "\u{AC01}"]),
        ("\u{903}\u{308}\u{AC01}", &["\u{903}\u{308}", "\u{AC01}"]),
        ("\u{903}\u{1F1E6}", &["\u{903}", "\u{1F1E6}"]),
        ("\u{903}\u{308}\u{1F1E6}", &["\u{903}\u{308}", "\u{1F1E6}"]),
        ("\u{903}\u{378}", &["\u{903}", "\u{378}"]),
        ("\u{903}\u{308}\u{378}", &["\u{903}\u{308}", "\u{378}"]),
        ("\u{1100}\u{20}", &["\u{1100}", "\u{20}"]),
        ("\u{1100}\u{308}\u{20}", &["\u{1100}\u{308}", "\u{20}"]),
        ("\u{1100}\u{D}", &["\u{1100}", "\u{D}"]),
        ("\u{1100}\u{308}\u{D}", &["\u{1100}\u{308}", "\u{D}"]),
        ("\u{1100}\u{A}", &["\u{1100}", "\u{A}"]),
        ("\u{1100}\u{308}\u{A}", &["\u{1100}\u{308}", "\u{A}"]),
        ("\u{1100}\u{1}", &["\u{1100}", "\u{1}"]),
        ("\u{1100}\u{308}\u{1}", &["\u{1100}\u{308}", "\u{1}"]),
        ("\u{1100}\u{300}", &["\u{1100}\u{300}"]),
        ("\u{1100}\u{308}\u{300}", &["\u{1100}\u{308}\u{300}"]),
        ("\u{1100}\u{1100}", &["\u{1100}\u{1100}"]),
        ("\u{1100}\u{308}\u{1100}", &["\u{1100}\u{308}", "\u{1100}"]),
        ("\u{1100}\u{1160}", &["\u{1100}\u{1160}"]),
        ("\u{1100}\u{308}\u{1160}", &["\u{1100}\u{308}", "\u{1160}"]),
        ("\u{1100}\u{11A8}", &["\u{1100}", "\u{11A8}"]),
        ("\u{1100}\u{308}\u{11A8}", &["\u{1100}\u{308}", "\u{11A8}"]),
        ("\u{1100}\u{AC00}", &["\u{1100}\u{AC00}"]),
        ("\u{1100}\u{308}\u{AC00}", &["\u{1100}\u{308}", "\u{AC00}"]),
        ("\u{1100}\u{AC01}", &["\u{1100}\u{AC01}"]),
        ("\u{1100}\u{308}\u{AC01}", &["\u{1100}\u{308}", "\u{AC01}"]),
        ("\u{1100}\u{1F1E6}", &["\u{1100}", "\u{1F1E6}"]),
        ("\u{1100}\u{308}\u{1F1E6}", &["\u{1100}\u{308}", "\u{1F1E6}"]),
        ("\u{1100}\u{378}", &["\u{1100}", "\u{378}"]),
        ("\u{1100}\u{308}\u{378}", &["\u{1100}\u{308}", "\u{378}"]),
        ("\u{1160}\u{20}", &["\u{1160}", "\u{20}"]),
        ("\u{1160}\u{308}\u{20}", &["\u{1160}\u{308}", "\u{20}"]),
        ("\u{1160}\u{D}", &["\u{1160}", "\u{D}"]),
        ("\u{1160}\u{308}\u{D}", &["\u{1160}\u{308}", "\u{D}"]),
        ("\u{1160}\u{A}", &["\u{1160}", "\u{A}"]),
        ("\u{1160}\u{308}\u{A}", &["\u{1160}\u{308}", "\u{A}"]),
        ("\u{1160}\u{1}", &["\u{1160}", "\u{1}"]),
        ("\u{1160}\u{308}\u{1}", &["\u{1160}\u{308}", "\u{1}"]),
        ("\u{1160}\u{300}", &["\u{1160}\u{300}"]),
        ("\u{1160}\u{308}\u{300}", &["\u{1160}\u{308}\u{300}"]),
        ("\u{1160}\u{1100}", &["\u{1160}", "\u{1100}"]),
        ("\u{1160}\u{308}\u{1100}", &["\u{1160}\u{308}", "\u{1100}"]),
        ("\u{1160}\u{1160}", &["\u{1160}\u{1160}"]),
        ("\u{1160}\u{308}\u{1160}", &["\u{1160}\u{308}", "\u{1160}"]),
        ("\u{1160}\u{11A8}", &["\u{1160}\u{11A8}"]),
        ("\u{1160}\u{308}\u{11A8}", &["\u{1160}\u{308}", "\u{11A8}"]),
        ("\u{1160}\u{AC00}", &["\u{1160}", "\u{AC00}"]),
        ("\u{1160}\u{308}\u{AC00}", &["\u{1160}\u{308}", "\u{AC00}"]),
        ("\u{1160}\u{AC01}", &["\u{1160}", "\u{AC01}"]),
        ("\u{1160}\u{308}\u{AC01}", &["\u{1160}\u{308}", "\u{AC01}"]),
        ("\u{1160}\u{1F1E6}", &["\u{1160}", "\u{1F1E6}"]),
        ("\u{1160}\u{308}\u{1F1E6}", &["\u{1160}\u{308}", "\u{1F1E6}"]),
        ("\u{1160}\u{378}", &["\u{1160}", "\u{378}"]),
        ("\u{1160}\u{308}\u{378}", &["\u{1160}\u{308}", "\u{378}"]),
        ("\u{11A8}\u{20}", &["\u{11A8}", "\u{20}"]),
        ("\u{11A8}\u{308}\u{20}", &["\u{11A8}\u{308}", "\u{20}"]),
        ("\u{11A8}\u{D}", &["\u{11A8}", "\u{D}"]),
        ("\u{11A8}\u{308}\u{D}", &["\u{11A8}\u{308}", "\u{D}"]),
        ("\u{11A8}\u{A}", &["\u{11A8}", "\u{A}"]),
        ("\u{11A8}\u{308}\u{A}", &["\u{11A8}\u{308}", "\u{A}"]),
        ("\u{11A8}\u{1}", &["\u{11A8}", "\u{1}"]),
        ("\u{11A8}\u{308}\u{1}", &["\u{11A8}\u{308}", "\u{1}"]),
        ("\u{11A8}\u{300}", &["\u{11A8}\u{300}"]),
        ("\u{11A8}\u{308}\u{300}", &["\u{11A8}\u{308}\u{300}"]),
        ("\u{11A8}\u{1100}", &["\u{11A8}", "\u{1100}"]),
        ("\u{11A8}\u{308}\u{1100}", &["\u{11A8}\u{308}", "\u{1100}"]),
        ("\u{11A8}\u{1160}", &["\u{11A8}", "\u{1160}"]),
        ("\u{11A8}\u{308}\u{1160}", &["\u{11A8}\u{308}", "\u{1160}"]),
        ("\u{11A8}\u{11A8}", &["\u{11A8}\u{11A8}"]),
        ("\u{11A8}\u{308}\u{11A8}", &["\u{11A8}\u{308}", "\u{11A8}"]),
        ("\u{11A8}\u{AC00}", &["\u{11A8}", "\u{AC00}"]),
        ("\u{11A8}\u{308}\u{AC00}", &["\u{11A8}\u{308}", "\u{AC00}"]),
        ("\u{11A8}\u{AC01}", &["\u{11A8}", "\u{AC01}"]),
        ("\u{11A8}\u{308}\u{AC01}", &["\u{11A8}\u{308}", "\u{AC01}"]),
        ("\u{11A8}\u{1F1E6}", &["\u{11A8}", "\u{1F1E6}"]),
        ("\u{11A8}\u{308}\u{1F1E6}", &["\u{11A8}\u{308}", "\u{1F1E6}"]),
        ("\u{11A8}\u{378}", &["\u{11A8}", "\u{378}"]),
        ("\u{11A8}\u{308}\u{378}", &["\u{11A8}\u{308}", "\u{378}"]),
        ("\u{AC00}\u{20}", &["\u{AC00}", "\u{20}"]),
        ("\u{AC00}\u{308}\u{20}", &["\u{AC00}\u{308}", "\u{20}"]),
        ("\u{AC00}\u{D}", &["\u{AC00}", "\u{D}"]),
        ("\u{AC00}\u{308}\u{D}", &["\u{AC00}\u{308}", "\u{D}"]),
        ("\u{AC00}\u{A}", &["\u{AC00}", "\u{A}"]),
        ("\u{AC00}\u{308}\u{A}", &["\u{AC00}\u{308}", "\u{A}"]),
        ("\u{AC00}\u{1}", &["\u{AC00}", "\u{1}"]),
        ("\u{AC00}\u{308}\u{1}", &["\u{AC00}\u{308}", "\u{1}"]),
        ("\u{AC00}\u{300}", &["\u{AC00}\u{300}"]),
        ("\u{AC00}\u{308}\u{300}", &["\u{AC00}\u{308}\u{300}"]),
        ("\u{AC00}\u{1100}", &["\u{AC00}", "\u{1100}"]),
        ("\u{AC00}\u{308}\u{1100}", &["\u{AC00}\u{308}", "\u{1100}"]),
        ("\u{AC00}\u{1160}", &["\u{AC00}\u{1160}"]),
        ("\u{AC00}\u{308}\u{1160}", &["\u{AC00}\u{308}", "\u{1160}"]),
        ("\u{AC00}\u{11A8}", &["\u{AC00}\u{11A8}"]),
        ("\u{AC00}\u{308}\u{11A8}", &["\u{AC00}\u{308}", "\u{11A8}"]),
        ("\u{AC00}\u{AC00}", &["\u{AC00}", "\u{AC00}"]),
        ("\u{AC00}\u{308}\u{AC00}", &["\u{AC00}\u{308}", "\u{AC00}"]),
        ("\u{AC00}\u{AC01}", &["\u{AC00}", "\u{AC01}"]),
        ("\u{AC00}\u{308}\u{AC01}", &["\u{AC00}\u{308}", "\u{AC01}"]),
        ("\u{AC00}\u{1F1E6}", &["\u{AC00}", "\u{1F1E6}"]),
        ("\u{AC00}\u{308}\u{1F1E6}", &["\u{AC00}\u{308}", "\u{1F1E6}"]),
        ("\u{AC00}\u{378}", &["\u{AC00}", "\u{378}"]),
        ("\u{AC00}\u{308}\u{378}", &["\u{AC00}\u{308}", "\u{378}"]),
        ("\u{AC01}\u{20}", &["\u{AC01}", "\u{20}"]),
        ("\u{AC01}\u{308}\u{20}", &["\u{AC01}\u{308}", "\u{20}"]),
        ("\u{AC01}\u{D}", &["\u{AC01}", "\u{D}"]),
        ("\u{AC01}\u{308}\u{D}", &["\u{AC01}\u{308}", "\u{D}"]),
        ("\u{AC01}\u{A}", &["\u{AC01}", "\u{A}"]),
        ("\u{AC01}\u{308}\u{A}", &["\u{AC01}\u{308}", "\u{A}"]),
        ("\u{AC01}\u{1}", &["\u{AC01}", "\u{1}"]),
        ("\u{AC01}\u{308}\u{1}", &["\u{AC01}\u{308}", "\u{1}"]),
        ("\u{AC01}\u{300}", &["\u{AC01}\u{300}"]),
        ("\u{AC01}\u{308}\u{300}", &["\u{AC01}\u{308}\u{300}"]),
        ("\u{AC01}\u{1100}", &["\u{AC01}", "\u{1100}"]),
        ("\u{AC01}\u{308}\u{1100}", &["\u{AC01}\u{308}", "\u{1100}"]),
        ("\u{AC01}\u{1160}", &["\u{AC01}", "\u{1160}"]),
        ("\u{AC01}\u{308}\u{1160}", &["\u{AC01}\u{308}", "\u{1160}"]),
        ("\u{AC01}\u{11A8}", &["\u{AC01}\u{11A8}"]),
        ("\u{AC01}\u{308}\u{11A8}", &["\u{AC01}\u{308}", "\u{11A8}"]),
        ("\u{AC01}\u{AC00}", &["\u{AC01}", "\u{AC00}"]),
        ("\u{AC01}\u{308}\u{AC00}", &["\u{AC01}\u{308}", "\u{AC00}"]),
        ("\u{AC01}\u{AC01}", &["\u{AC01}", "\u{AC01}"]),
        ("\u{AC01}\u{308}\u{AC01}", &["\u{AC01}\u{308}", "\u{AC01}"]),
        ("\u{AC01}\u{1F1E6}", &["\u{AC01}", "\u{1F1E6}"]),
        ("\u{AC01}\u{308}\u{1F1E6}", &["\u{AC01}\u{308}", "\u{1F1E6}"]),
        ("\u{AC01}\u{378}", &["\u{AC01}", "\u{378}"]),
        ("\u{AC01}\u{308}\u{378}", &["\u{AC01}\u{308}", "\u{378}"]),
        ("\u{1F1E6}\u{20}", &["\u{1F1E6}", "\u{20}"]),
        ("\u{1F1E6}\u{308}\u{20}", &["\u{1F1E6}\u{308}", "\u{20}"]),
        ("\u{1F1E6}\u{D}", &["\u{1F1E6}", "\u{D}"]),
        ("\u{1F1E6}\u{308}\u{D}", &["\u{1F1E6}\u{308}", "\u{D}"]),
        ("\u{1F1E6}\u{A}", &["\u{1F1E6}", "\u{A}"]),
        ("\u{1F1E6}\u{308}\u{A}", &["\u{1F1E6}\u{308}", "\u{A}"]),
        ("\u{1F1E6}\u{1}", &["\u{1F1E6}", "\u{1}"]),
        ("\u{1F1E6}\u{308}\u{1}", &["\u{1F1E6}\u{308}", "\u{1}"]),
        ("\u{1F1E6}\u{300}", &["\u{1F1E6}\u{300}"]),
        ("\u{1F1E6}\u{308}\u{300}", &["\u{1F1E6}\u{308}\u{300}"]),
        ("\u{1F1E6}\u{1100}", &["\u{1F1E6}", "\u{1100}"]),
        ("\u{1F1E6}\u{308}\u{1100}", &["\u{1F1E6}\u{308}", "\u{1100}"]),
        ("\u{1F1E6}\u{1160}", &["\u{1F1E6}", "\u{1160}"]),
        ("\u{1F1E6}\u{308}\u{1160}", &["\u{1F1E6}\u{308}", "\u{1160}"]),
        ("\u{1F1E6}\u{11A8}", &["\u{1F1E6}", "\u{11A8}"]),
        ("\u{1F1E6}\u{308}\u{11A8}", &["\u{1F1E6}\u{308}", "\u{11A8}"]),
        ("\u{1F1E6}\u{AC00}", &["\u{1F1E6}", "\u{AC00}"]),
        ("\u{1F1E6}\u{308}\u{AC00}", &["\u{1F1E6}\u{308}", "\u{AC00}"]),
        ("\u{1F1E6}\u{AC01}", &["\u{1F1E6}", "\u{AC01}"]),
        ("\u{1F1E6}\u{308}\u{AC01}", &["\u{1F1E6}\u{308}", "\u{AC01}"]),
        ("\u{1F1E6}\u{1F1E6}", &["\u{1F1E6}\u{1F1E6}"]),
        ("\u{1F1E6}\u{308}\u{1F1E6}", &["\u{1F1E6}\u{308}", "\u{1F1E6}"]),
        ("\u{1F1E6}\u{378}", &["\u{1F1E6}", "\u{378}"]),
        ("\u{1F1E6}\u{308}\u{378}", &["\u{1F1E6}\u{308}", "\u{378}"]),
        ("\u{378}\u{20}", &["\u{378}", "\u{20}"]),
        ("\u{378}\u{308}\u{20}", &["\u{378}\u{308}", "\u{20}"]),
        ("\u{378}\u{D}", &["\u{378}", "\u{D}"]),
        ("\u{378}\u{308}\u{D}", &["\u{378}\u{308}", "\u{D}"]),
        ("\u{378}\u{A}", &["\u{378}", "\u{A}"]),
        ("\u{378}\u{308}\u{A}", &["\u{378}\u{308}", "\u{A}"]),
        ("\u{378}\u{1}", &["\u{378}", "\u{1}"]),
        ("\u{378}\u{308}\u{1}", &["\u{378}\u{308}", "\u{1}"]),
        ("\u{378}\u{300}", &["\u{378}\u{300}"]),
        ("\u{378}\u{308}\u{300}", &["\u{378}\u{308}\u{300}"]),
        ("\u{378}\u{1100}", &["\u{378}", "\u{1100}"]),
        ("\u{378}\u{308}\u{1100}", &["\u{378}\u{308}", "\u{1100}"]),
        ("\u{378}\u{1160}", &["\u{378}", "\u{1160}"]),
        ("\u{378}\u{308}\u{1160}", &["\u{378}\u{308}", "\u{1160}"]),
        ("\u{378}\u{11A8}", &["\u{378}", "\u{11A8}"]),
        ("\u{378}\u{308}\u{11A8}", &["\u{378}\u{308}", "\u{11A8}"]),
        ("\u{378}\u{AC00}", &["\u{378}", "\u{AC00}"]),
        ("\u{378}\u{308}\u{AC00}", &["\u{378}\u{308}", "\u{AC00}"]),
        ("\u{378}\u{AC01}", &["\u{378}", "\u{AC01}"]),
        ("\u{378}\u{308}\u{AC01}", &["\u{378}\u{308}", "\u{AC01}"]),
        ("\u{378}\u{1F1E6}", &["\u{378}", "\u{1F1E6}"]),
        ("\u{378}\u{308}\u{1F1E6}", &["\u{378}\u{308}", "\u{1F1E6}"]),
        ("\u{378}\u{378}", &["\u{378}", "\u{378}"]),
        ("\u{378}\u{308}\u{378}", &["\u{378}\u{308}", "\u{378}"]),
        ("\u{61}\u{1F1E6}\u{62}", &["\u{61}", "\u{1F1E6}", "\u{62}"]),
        ("\u{1F1F7}\u{1F1FA}", &["\u{1F1F7}\u{1F1FA}"]),
        ("\u{1F1F7}\u{1F1FA}\u{1F1F8}", &["\u{1F1F7}\u{1F1FA}\u{1F1F8}"]),
        ("\u{1F1F7}\u{1F1FA}\u{1F1F8}\u{1F1EA}",
        &["\u{1F1F7}\u{1F1FA}\u{1F1F8}\u{1F1EA}"]),
        ("\u{1F1F7}\u{1F1FA}\u{200B}\u{1F1F8}\u{1F1EA}",
         &["\u{1F1F7}\u{1F1FA}", "\u{200B}", "\u{1F1F8}\u{1F1EA}"]),
        ("\u{1F1E6}\u{1F1E7}\u{1F1E8}", &["\u{1F1E6}\u{1F1E7}\u{1F1E8}"]),
        ("\u{1F1E6}\u{200D}\u{1F1E7}\u{1F1E8}", &["\u{1F1E6}\u{200D}",
         "\u{1F1E7}\u{1F1E8}"]),
        ("\u{1F1E6}\u{1F1E7}\u{200D}\u{1F1E8}",
         &["\u{1F1E6}\u{1F1E7}\u{200D}", "\u{1F1E8}"]),
        ("\u{20}\u{200D}\u{646}", &["\u{20}\u{200D}", "\u{646}"]),
        ("\u{646}\u{200D}\u{20}", &["\u{646}\u{200D}", "\u{20}"]),
    ];

    let test_diff: [(_, &[_], &[_]); 23] = [
        ("\u{20}\u{903}", &["\u{20}\u{903}"], &["\u{20}", "\u{903}"]), ("\u{20}\u{308}\u{903}",
        &["\u{20}\u{308}\u{903}"], &["\u{20}\u{308}", "\u{903}"]), ("\u{D}\u{308}\u{903}",
        &["\u{D}", "\u{308}\u{903}"], &["\u{D}", "\u{308}", "\u{903}"]), ("\u{A}\u{308}\u{903}",
        &["\u{A}", "\u{308}\u{903}"], &["\u{A}", "\u{308}", "\u{903}"]), ("\u{1}\u{308}\u{903}",
        &["\u{1}", "\u{308}\u{903}"], &["\u{1}", "\u{308}", "\u{903}"]), ("\u{300}\u{903}",
        &["\u{300}\u{903}"], &["\u{300}", "\u{903}"]), ("\u{300}\u{308}\u{903}",
        &["\u{300}\u{308}\u{903}"], &["\u{300}\u{308}", "\u{903}"]), ("\u{903}\u{903}",
        &["\u{903}\u{903}"], &["\u{903}", "\u{903}"]), ("\u{903}\u{308}\u{903}",
        &["\u{903}\u{308}\u{903}"], &["\u{903}\u{308}", "\u{903}"]), ("\u{1100}\u{903}",
        &["\u{1100}\u{903}"], &["\u{1100}", "\u{903}"]), ("\u{1100}\u{308}\u{903}",
        &["\u{1100}\u{308}\u{903}"], &["\u{1100}\u{308}", "\u{903}"]), ("\u{1160}\u{903}",
        &["\u{1160}\u{903}"], &["\u{1160}", "\u{903}"]), ("\u{1160}\u{308}\u{903}",
        &["\u{1160}\u{308}\u{903}"], &["\u{1160}\u{308}", "\u{903}"]), ("\u{11A8}\u{903}",
        &["\u{11A8}\u{903}"], &["\u{11A8}", "\u{903}"]), ("\u{11A8}\u{308}\u{903}",
        &["\u{11A8}\u{308}\u{903}"], &["\u{11A8}\u{308}", "\u{903}"]), ("\u{AC00}\u{903}",
        &["\u{AC00}\u{903}"], &["\u{AC00}", "\u{903}"]), ("\u{AC00}\u{308}\u{903}",
        &["\u{AC00}\u{308}\u{903}"], &["\u{AC00}\u{308}", "\u{903}"]), ("\u{AC01}\u{903}",
        &["\u{AC01}\u{903}"], &["\u{AC01}", "\u{903}"]), ("\u{AC01}\u{308}\u{903}",
        &["\u{AC01}\u{308}\u{903}"], &["\u{AC01}\u{308}", "\u{903}"]), ("\u{1F1E6}\u{903}",
        &["\u{1F1E6}\u{903}"], &["\u{1F1E6}", "\u{903}"]), ("\u{1F1E6}\u{308}\u{903}",
        &["\u{1F1E6}\u{308}\u{903}"], &["\u{1F1E6}\u{308}", "\u{903}"]), ("\u{378}\u{903}",
        &["\u{378}\u{903}"], &["\u{378}", "\u{903}"]), ("\u{378}\u{308}\u{903}",
        &["\u{378}\u{308}\u{903}"], &["\u{378}\u{308}", "\u{903}"]),
    ];

    for &(s, g) in &test_same[..] {
        // test forward iterator
        assert!(order::equals(s.graphemes(true), g.iter().cloned()));
        assert!(order::equals(s.graphemes(false), g.iter().cloned()));

        // test reverse iterator
        assert!(order::equals(s.graphemes(true).rev(), g.iter().rev().cloned()));
        assert!(order::equals(s.graphemes(false).rev(), g.iter().rev().cloned()));
    }

    for &(s, gt, gf) in &test_diff {
        // test forward iterator
        assert!(order::equals(s.graphemes(true), gt.iter().cloned()));
        assert!(order::equals(s.graphemes(false), gf.iter().cloned()));

        // test reverse iterator
        assert!(order::equals(s.graphemes(true).rev(), gt.iter().rev().cloned()));
        assert!(order::equals(s.graphemes(false).rev(), gf.iter().rev().cloned()));
    }

    // test the indices iterators
    let s = "a̐éö̲\r\n";
    let gr_inds = s.grapheme_indices(true).collect::<Vec<(usize, &str)>>();
    let b: &[_] = &[(0, "a̐"), (3, "é"), (6, "ö̲"), (11, "\r\n")];
    assert_eq!(gr_inds, b);
    let gr_inds = s.grapheme_indices(true).rev().collect::<Vec<(usize, &str)>>();
    let b: &[_] = &[(11, "\r\n"), (6, "ö̲"), (3, "é"), (0, "a̐")];
    assert_eq!(gr_inds, b);
    let mut gr_inds_iter = s.grapheme_indices(true);
    {
        let gr_inds = gr_inds_iter.by_ref();
        let e1 = gr_inds.size_hint();
        assert_eq!(e1, (1, Some(13)));
        let c = gr_inds.count();
        assert_eq!(c, 4);
    }
    let e2 = gr_inds_iter.size_hint();
    assert_eq!(e2, (0, Some(0)));

    // make sure the reverse iterator does the right thing with "\n" at beginning of string
    let s = "\n\r\n\r";
    let gr = s.graphemes(true).rev().collect::<Vec<&str>>();
    let b: &[_] = &["\r", "\r\n", "\n"];
    assert_eq!(gr, b);
}

#[test]
fn test_splitator() {
    fn t(s: &str, sep: &str, u: &[&str]) {
        let v: Vec<&str> = s.split(sep).collect();
        assert_eq!(v, u);
    }
    t("--1233345--", "12345", &["--1233345--"]);
    t("abc::hello::there", "::", &["abc", "hello", "there"]);
    t("::hello::there", "::", &["", "hello", "there"]);
    t("hello::there::", "::", &["hello", "there", ""]);
    t("::hello::there::", "::", &["", "hello", "there", ""]);
    t("ประเทศไทย中华Việt Nam", "中华", &["ประเทศไทย", "Việt Nam"]);
    t("zzXXXzzYYYzz", "zz", &["", "XXX", "YYY", ""]);
    t("zzXXXzYYYz", "XXX", &["zz", "zYYYz"]);
    t(".XXX.YYY.", ".", &["", "XXX", "YYY", ""]);
    t("", ".", &[""]);
    t("zz", "zz", &["",""]);
    t("ok", "z", &["ok"]);
    t("zzz", "zz", &["","z"]);
    t("zzzzz", "zz", &["","","z"]);
}

#[test]
fn test_str_default() {
    use std::default::Default;

    fn t<S: Default + AsRef<str>>() {
        let s: S = Default::default();
        assert_eq!(s.as_ref(), "");
    }

    t::<&str>();
    t::<String>();
}

#[test]
fn test_str_container() {
    fn sum_len(v: &[&str]) -> usize {
        v.iter().map(|x| x.len()).sum()
    }

    let s = String::from_str("01234");
    assert_eq!(5, sum_len(&["012", "", "34"]));
    assert_eq!(5, sum_len(&[&String::from_str("01"),
                            &String::from_str("2"),
                            &String::from_str("34"),
                            &String::from_str("")]));
    assert_eq!(5, sum_len(&[&s]));
}

#[test]
fn test_str_from_utf8() {
    let xs = b"hello";
    assert_eq!(from_utf8(xs), Ok("hello"));

    let xs = "ศไทย中华Việt Nam".as_bytes();
    assert_eq!(from_utf8(xs), Ok("ศไทย中华Việt Nam"));

    let xs = b"hello\xFF";
    assert_eq!(from_utf8(xs), Err(Utf8Error::TooShort));
}

mod bench {
    use test::{Bencher, black_box};

    #[bench]
    fn char_iterator(b: &mut Bencher) {
        let s = "ศไทย中华Việt Nam; Mary had a little lamb, Little lamb";

        b.iter(|| s.chars().count());
    }

    #[bench]
    fn char_iterator_for(b: &mut Bencher) {
        let s = "ศไทย中华Việt Nam; Mary had a little lamb, Little lamb";

        b.iter(|| {
            for ch in s.chars() { black_box(ch); }
        });
    }

    #[bench]
    fn char_iterator_ascii(b: &mut Bencher) {
        let s = "Mary had a little lamb, Little lamb
        Mary had a little lamb, Little lamb
        Mary had a little lamb, Little lamb
        Mary had a little lamb, Little lamb
        Mary had a little lamb, Little lamb
        Mary had a little lamb, Little lamb";

        b.iter(|| s.chars().count());
    }

    #[bench]
    fn char_iterator_rev(b: &mut Bencher) {
        let s = "ศไทย中华Việt Nam; Mary had a little lamb, Little lamb";

        b.iter(|| s.chars().rev().count());
    }

    #[bench]
    fn char_iterator_rev_for(b: &mut Bencher) {
        let s = "ศไทย中华Việt Nam; Mary had a little lamb, Little lamb";

        b.iter(|| {
            for ch in s.chars().rev() { black_box(ch); }
        });
    }

    #[bench]
    fn char_indicesator(b: &mut Bencher) {
        let s = "ศไทย中华Việt Nam; Mary had a little lamb, Little lamb";
        let len = s.chars().count();

        b.iter(|| assert_eq!(s.char_indices().count(), len));
    }

    #[bench]
    fn char_indicesator_rev(b: &mut Bencher) {
        let s = "ศไทย中华Việt Nam; Mary had a little lamb, Little lamb";
        let len = s.chars().count();

        b.iter(|| assert_eq!(s.char_indices().rev().count(), len));
    }

    #[bench]
    fn split_unicode_ascii(b: &mut Bencher) {
        let s = "ประเทศไทย中华Việt Namประเทศไทย中华Việt Nam";

        b.iter(|| assert_eq!(s.split('V').count(), 3));
    }

    #[bench]
    fn split_ascii(b: &mut Bencher) {
        let s = "Mary had a little lamb, Little lamb, little-lamb.";
        let len = s.split(' ').count();

        b.iter(|| assert_eq!(s.split(' ').count(), len));
    }

    #[bench]
    fn split_extern_fn(b: &mut Bencher) {
        let s = "Mary had a little lamb, Little lamb, little-lamb.";
        let len = s.split(' ').count();
        fn pred(c: char) -> bool { c == ' ' }

        b.iter(|| assert_eq!(s.split(pred).count(), len));
    }

    #[bench]
    fn split_closure(b: &mut Bencher) {
        let s = "Mary had a little lamb, Little lamb, little-lamb.";
        let len = s.split(' ').count();

        b.iter(|| assert_eq!(s.split(|c: char| c == ' ').count(), len));
    }

    #[bench]
    fn split_slice(b: &mut Bencher) {
        let s = "Mary had a little lamb, Little lamb, little-lamb.";
        let len = s.split(' ').count();

        let c: &[char] = &[' '];
        b.iter(|| assert_eq!(s.split(c).count(), len));
    }

    #[bench]
    fn bench_connect(b: &mut Bencher) {
        let s = "ศไทย中华Việt Nam; Mary had a little lamb, Little lamb";
        let sep = "→";
        let v = vec![s, s, s, s, s, s, s, s, s, s];
        b.iter(|| {
            assert_eq!(v.connect(sep).len(), s.len() * 10 + sep.len() * 9);
        })
    }

    #[bench]
    fn bench_contains_short_short(b: &mut Bencher) {
        let haystack = "Lorem ipsum dolor sit amet, consectetur adipiscing elit.";
        let needle = "sit";

        b.iter(|| {
            assert!(haystack.contains(needle));
        })
    }

    #[bench]
    fn bench_contains_short_long(b: &mut Bencher) {
        let haystack = "\
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse quis lorem sit amet dolor \
ultricies condimentum. Praesent iaculis purus elit, ac malesuada quam malesuada in. Duis sed orci \
eros. Suspendisse sit amet magna mollis, mollis nunc luctus, imperdiet mi. Integer fringilla non \
sem ut lacinia. Fusce varius tortor a risus porttitor hendrerit. Morbi mauris dui, ultricies nec \
tempus vel, gravida nec quam.

In est dui, tincidunt sed tempus interdum, adipiscing laoreet ante. Etiam tempor, tellus quis \
sagittis interdum, nulla purus mattis sem, quis auctor erat odio ac tellus. In nec nunc sit amet \
diam volutpat molestie at sed ipsum. Vestibulum laoreet consequat vulputate. Integer accumsan \
lorem ac dignissim placerat. Suspendisse convallis faucibus lorem. Aliquam erat volutpat. In vel \
eleifend felis. Sed suscipit nulla lorem, sed mollis est sollicitudin et. Nam fermentum egestas \
interdum. Curabitur ut nisi justo.

Sed sollicitudin ipsum tellus, ut condimentum leo eleifend nec. Cras ut velit ante. Phasellus nec \
mollis odio. Mauris molestie erat in arcu mattis, at aliquet dolor vehicula. Quisque malesuada \
lectus sit amet nisi pretium, a condimentum ipsum porta. Morbi at dapibus diam. Praesent egestas \
est sed risus elementum, eu rutrum metus ultrices. Etiam fermentum consectetur magna, id rutrum \
felis accumsan a. Aliquam ut pellentesque libero. Sed mi nulla, lobortis eu tortor id, suscipit \
ultricies neque. Morbi iaculis sit amet risus at iaculis. Praesent eget ligula quis turpis \
feugiat suscipit vel non arcu. Interdum et malesuada fames ac ante ipsum primis in faucibus. \
Aliquam sit amet placerat lorem.

Cras a lacus vel ante posuere elementum. Nunc est leo, bibendum ut facilisis vel, bibendum at \
mauris. Nullam adipiscing diam vel odio ornare, luctus adipiscing mi luctus. Nulla facilisi. \
Mauris adipiscing bibendum neque, quis adipiscing lectus tempus et. Sed feugiat erat et nisl \
lobortis pharetra. Donec vitae erat enim. Nullam sit amet felis et quam lacinia tincidunt. Aliquam \
suscipit dapibus urna. Sed volutpat urna in magna pulvinar volutpat. Phasellus nec tellus ac diam \
cursus accumsan.

Nam lectus enim, dapibus non nisi tempor, consectetur convallis massa. Maecenas eleifend dictum \
feugiat. Etiam quis mauris vel risus luctus mattis a a nunc. Nullam orci quam, imperdiet id \
vehicula in, porttitor ut nibh. Duis sagittis adipiscing nisl vitae congue. Donec mollis risus eu \
leo suscipit, varius porttitor nulla porta. Pellentesque ut sem nec nisi euismod vehicula. Nulla \
malesuada sollicitudin quam eu fermentum.";
        let needle = "english";

        b.iter(|| {
            assert!(!haystack.contains(needle));
        })
    }

    #[bench]
    fn bench_contains_bad_naive(b: &mut Bencher) {
        let haystack = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
        let needle = "aaaaaaaab";

        b.iter(|| {
            assert!(!haystack.contains(needle));
        })
    }

    #[bench]
    fn bench_contains_equal(b: &mut Bencher) {
        let haystack = "Lorem ipsum dolor sit amet, consectetur adipiscing elit.";
        let needle = "Lorem ipsum dolor sit amet, consectetur adipiscing elit.";

        b.iter(|| {
            assert!(haystack.contains(needle));
        })
    }
}