#![allow(clippy::should_panic_without_expect)]
#![cfg_attr(feature = "nightly_assert_matches", feature(assert_matches))]

#[cfg(feature = "nightly_assert_matches")]
use std::assert_matches::assert_matches;
//use std::borrow::Cow;
//use std::cell::Cell;
//use std::collections::TryReserveErrorKind::*;
//use std::ops::Bound;
//use std::ops::Bound::*;
//use std::ops::RangeBounds;
//use std::panic;
//use std::str;

// This are the tests from rusts library/alloc/tests/string.rs with String=CowStr aliased Long
// term plan is to make CowStr reasonable compatible with String. This still does not mean
// *everything*. For now this is just made to pass by commenting out anything that's failing
// and adding some remarks.

use cowstr::CowStr as String;
use cowstr::ToCowStr;

// NOTE: CowStr will never implement Cow as its main purpose is to have this functionality
//       built-in
//pub trait IntoCow<'a, B: ?Sized> where B: ToOwned, { fn into_cow(self) -> Cow<'a,
// B>; }
//
// impl<'a> IntoCow<'a, str> for String {
//     fn into_cow(self) -> Cow<'a, str> {
//         Cow::Owned(self)
//     }
// }
//
// impl<'a> IntoCow<'a, str> for &'a str {
//     fn into_cow(self) -> Cow<'a, str> {
//         Cow::Borrowed(self)
//     }
// }

#[allow(clippy::option_as_ref_deref)]
#[test]
fn test_from_str() {
    let owned: Option<String> = "string".parse().ok();
    assert_eq!(owned.as_ref().map(|s| &**s), Some("string"));
}

// #[test]
// fn test_from_cow_str() {
//     assert_eq!(String::from(Cow::Borrowed("string")), "string");
//     assert_eq!(String::from(Cow::Owned(String::from("string"))), "string");
// }

#[test]
fn test_unsized_to_string() {
    let s: &str = "abc";
    let _: String = (*s).to_cowstr();
}

// PLANNED: see 'PLANNED' in cowstr, slightly different API
// #[test]
// fn test_from_utf8() {
//     let xs = b"hello".to_vec();
//     assert_eq!(String::from_utf8(xs).unwrap(), String::from("hello"));
//
//     let xs = "ศไทย中华Việt Nam".as_bytes().to_vec();
//     assert_eq!(
//         String::from_utf8(xs).unwrap(),
//         String::from("ศไทย中华Việt Nam")
//     );
//
//     let xs = b"hello\xFF".to_vec();
//     let err = String::from_utf8(xs).unwrap_err();
//     assert_eq!(err.as_bytes(), b"hello\xff");
//     let err_clone = err.clone();
//     assert_eq!(err, err_clone);
//     assert_eq!(err.into_bytes(), b"hello\xff".to_vec());
//     assert_eq!(err_clone.utf8_error().valid_up_to(), 5);
// }
//
// #[test]
// fn test_from_utf8_lossy() {
//     let xs = b"hello";
//     let ys: Cow<'_, str> = "hello".into_cow();
//     assert_eq!(String::from_utf8_lossy(xs), ys);
//
//     let xs = "ศไทย中华Việt Nam".as_bytes();
//     let ys: Cow<'_, str> = "ศไทย中华Việt Nam".into_cow();
//     assert_eq!(String::from_utf8_lossy(xs), ys);
//
//     let xs = b"Hello\xC2 There\xFF Goodbye";
//     assert_eq!(
//         String::from_utf8_lossy(xs),
//         String::from("Hello\u{FFFD} There\u{FFFD} Goodbye").into_cow()
//     );
//
//     let xs = b"Hello\xC0\x80 There\xE6\x83 Goodbye";
//     assert_eq!(
//         String::from_utf8_lossy(xs),
//         String::from("Hello\u{FFFD}\u{FFFD} There\u{FFFD} Goodbye").into_cow()
//     );
//
//     let xs = b"\xF5foo\xF5\x80bar";
//     assert_eq!(
//         String::from_utf8_lossy(xs),
//         String::from("\u{FFFD}foo\u{FFFD}\u{FFFD}bar").into_cow()
//     );
//
//     let xs = b"\xF1foo\xF1\x80bar\xF1\x80\x80baz";
//     assert_eq!(
//         String::from_utf8_lossy(xs),
//         String::from("\u{FFFD}foo\u{FFFD}bar\u{FFFD}baz").into_cow()
//     );
//
//     let xs = b"\xF4foo\xF4\x80bar\xF4\xBFbaz";
//     assert_eq!(
//         String::from_utf8_lossy(xs),
//         String::from("\u{FFFD}foo\u{FFFD}bar\u{FFFD}\u{FFFD}baz").into_cow()
//     );
//
//     let xs = b"\xF0\x80\x80\x80foo\xF0\x90\x80\x80bar";
//     assert_eq!(
//         String::from_utf8_lossy(xs),
//         String::from("\u{FFFD}\u{FFFD}\u{FFFD}\u{FFFD}foo\u{10000}bar").into_cow()
//     );
//
//     // surrogates
//     let xs = b"\xED\xA0\x80foo\xED\xBF\xBFbar";
//     assert_eq!(
//         String::from_utf8_lossy(xs),
//         String::from("\u{FFFD}\u{FFFD}\u{FFFD}foo\u{FFFD}\u{FFFD}\u{FFFD}bar").into_cow()
//     );
// }

// PLANNED: see 'PLANNED' in cowstr, slightly different API
// #[test]
// fn test_from_utf16() {
//     let pairs = [
//         (
//             String::from("𐍅𐌿𐌻𐍆𐌹𐌻𐌰\n"),
//             vec![
//                 0xd800, 0xdf45, 0xd800, 0xdf3f, 0xd800, 0xdf3b, 0xd800, 0xdf46, 0xd800, 0xdf39,
//                 0xd800, 0xdf3b, 0xd800, 0xdf30, 0x000a,
//             ],
//         ),
//         (
//             String::from("𐐒𐑉𐐮𐑀𐐲𐑋 𐐏𐐲𐑍\n"),
//             vec![
//                 0xd801, 0xdc12, 0xd801, 0xdc49, 0xd801, 0xdc2e, 0xd801, 0xdc40, 0xd801, 0xdc32,
//                 0xd801, 0xdc4b, 0x0020, 0xd801, 0xdc0f, 0xd801, 0xdc32, 0xd801, 0xdc4d, 0x000a,
//             ],
//         ),
//         (
//             String::from("𐌀𐌖𐌋𐌄𐌑𐌉·𐌌𐌄𐌕𐌄𐌋𐌉𐌑\n"),
//             vec![
//                 0xd800, 0xdf00, 0xd800, 0xdf16, 0xd800, 0xdf0b, 0xd800, 0xdf04, 0xd800, 0xdf11,
//                 0xd800, 0xdf09, 0x00b7, 0xd800, 0xdf0c, 0xd800, 0xdf04, 0xd800, 0xdf15, 0xd800,
//                 0xdf04, 0xd800, 0xdf0b, 0xd800, 0xdf09, 0xd800, 0xdf11, 0x000a,
//             ],
//         ),
//         (
//             String::from("𐒋𐒘𐒈𐒑𐒛𐒒 𐒕𐒓 𐒈𐒚𐒍 𐒏𐒜𐒒𐒖𐒆 𐒕𐒆\n"),
//             vec![
//                 0xd801, 0xdc8b, 0xd801, 0xdc98, 0xd801, 0xdc88, 0xd801, 0xdc91, 0xd801, 0xdc9b,
//                 0xd801, 0xdc92, 0x0020, 0xd801, 0xdc95, 0xd801, 0xdc93, 0x0020, 0xd801, 0xdc88,
//                 0xd801, 0xdc9a, 0xd801, 0xdc8d, 0x0020, 0xd801, 0xdc8f, 0xd801, 0xdc9c, 0xd801,
//                 0xdc92, 0xd801, 0xdc96, 0xd801, 0xdc86, 0x0020, 0xd801, 0xdc95, 0xd801, 0xdc86,
//                 0x000a,
//             ],
//         ),
//         // Issue #12318, even-numbered non-BMP planes
//         (String::from("\u{20000}"), vec![0xD840, 0xDC00]),
//     ];
//
//     for p in &pairs {
//         let (s, u) = (*p).clone();
//         let s_as_utf16 = s.encode_utf16().collect::<Vec<u16>>();
//         let u_as_string = String::from_utf16(&u).unwrap();
//
//         assert!(core::char::decode_utf16(u.iter().cloned()).all(|r| r.is_ok()));
//         assert_eq!(s_as_utf16, u);
//
//         assert_eq!(u_as_string, s);
//         assert_eq!(String::from_utf16_lossy(&u), s);
//
//         assert_eq!(String::from_utf16(&s_as_utf16).unwrap(), s);
//         assert_eq!(u_as_string.encode_utf16().collect::<Vec<u16>>(), u);
//     }
// }
//
// #[test]
// fn test_utf16_invalid() {
//     // completely positive cases tested above.
//     // lead + eof
//     assert!(String::from_utf16(&[0xD800]).is_err());
//     // lead + lead
//     assert!(String::from_utf16(&[0xD800, 0xD800]).is_err());
//
//     // isolated trail
//     assert!(String::from_utf16(&[0x0061, 0xDC00]).is_err());
//
//     // general
//     assert!(String::from_utf16(&[0xD800, 0xd801, 0xdc8b, 0xD800]).is_err());
// }
//
// #[test]
// fn test_from_utf16_lossy() {
//     // completely positive cases tested above.
//     // lead + eof
//     assert_eq!(
//         String::from_utf16_lossy(&[0xD800]),
//         String::from("\u{FFFD}")
//     );
//     // lead + lead
//     assert_eq!(
//         String::from_utf16_lossy(&[0xD800, 0xD800]),
//         String::from("\u{FFFD}\u{FFFD}")
//     );
//
//     // isolated trail
//     assert_eq!(
//         String::from_utf16_lossy(&[0x0061, 0xDC00]),
//         String::from("a\u{FFFD}")
//     );
//
//     // general
//     assert_eq!(
//         String::from_utf16_lossy(&[0xD800, 0xd801, 0xdc8b, 0xD800]),
//         String::from("\u{FFFD}𐒋\u{FFFD}")
//     );
// }

// NOTE: CowStr has no underlying Vec, will never be implemented
// #[test]
// fn test_push_bytes() {
//     let mut s = String::from("ABC");
//     unsafe {
//         let mv = s.as_mut_vec();
//         mv.extend_from_slice(&[b'D']);
//     }
//     assert_eq!(s, "ABCD");
// }

#[test]
fn test_push_str() {
    let mut s = String::new();
    s.push_str("");
    assert_eq!(&s[0..], "");
    s.push_str("abc");
    assert_eq!(&s[0..], "abc");
    s.push_str("ประเทศไทย中华Việt Nam");
    assert_eq!(&s[0..], "abcประเทศไทย中华Việt Nam");
}

#[test]
fn test_add_assign() {
    let mut s = String::new();
    s += "";
    assert_eq!(s.as_str(), "");
    s += "abc";
    assert_eq!(s.as_str(), "abc");
    s += "ประเทศไทย中华Việt Nam";
    assert_eq!(s.as_str(), "abcประเทศไทย中华Việt Nam");
}

#[test]
fn test_push() {
    let mut data = String::from("ประเทศไทย中");
    data.push('华');
    data.push('b'); // 1 byte
    data.push('¢'); // 2 byte
    data.push('€'); // 3 byte
    data.push('𤭢'); // 4 byte
    assert_eq!(data, "ประเทศไทย中华b¢€𤭢");
}

#[test]
fn test_pop() {
    let mut data = String::from("ประเทศไทย中华b¢€𤭢");
    assert_eq!(data.pop().unwrap(), '𤭢'); // 4 bytes
    assert_eq!(data.pop().unwrap(), '€'); // 3 bytes
    assert_eq!(data.pop().unwrap(), '¢'); // 2 bytes
    assert_eq!(data.pop().unwrap(), 'b'); // 1 bytes
    assert_eq!(data.pop().unwrap(), '华');
    assert_eq!(data, "ประเทศไทย中");
}

// PLANNED:
// #[test]
// fn test_split_off_empty() {
//     let orig = "Hello, world!";
//     let mut split = String::from(orig);
//     let empty: String = split.split_off(orig.len());
//     assert!(empty.is_empty());
// }
//
// #[test]
// #[should_panic]
// fn test_split_off_past_end() {
//     let orig = "Hello, world!";
//     let mut split = String::from(orig);
//     let _ = split.split_off(orig.len() + 1);
// }
//
// #[test]
// #[should_panic]
// fn test_split_off_mid_char() {
//     let mut shan = String::from("山");
//     let _broken_mountain = shan.split_off(1);
// }
//
// #[test]
// fn test_split_off_ascii() {
//     let mut ab = String::from("ABCD");
//     let orig_capacity = ab.capacity();
//     let cd = ab.split_off(2);
//     assert_eq!(ab, "AB");
//     assert_eq!(cd, "CD");
//     assert_eq!(ab.capacity(), orig_capacity);
// }
//
// #[test]
// fn test_split_off_unicode() {
//     let mut nihon = String::from("日本語");
//     let orig_capacity = nihon.capacity();
//     let go = nihon.split_off("日本".len());
//     assert_eq!(nihon, "日本");
//     assert_eq!(go, "語");
//     assert_eq!(nihon.capacity(), orig_capacity);
// }

#[test]
fn test_str_truncate() {
    let mut s = String::from("12345");
    s.truncate(5);
    assert_eq!(s, "12345");
    s.truncate(3);
    assert_eq!(s, "123");
    s.truncate(0);
    assert_eq!(s, "");

    let mut s = String::from("12345");
    let p = s.as_ptr();
    s.truncate(3);
    s.push_str("6");
    let p_ = s.as_ptr();
    assert_eq!(p_, p);
}

#[test]
fn test_str_truncate_invalid_len() {
    let mut s = String::from("12345");
    s.truncate(6);
    assert_eq!(s, "12345");
}

#[test]
#[should_panic]
fn test_str_truncate_split_codepoint() {
    let mut s = String::from("\u{FC}"); // ü
    s.truncate(1);
}

#[test]
fn test_str_clear() {
    let mut s = String::from("12345");
    s.clear();
    assert_eq!(s.len(), 0);
    assert_eq!(s, "");
}

#[test]
fn test_str_add() {
    let a = String::from("12345");
    let b = a + "2";
    let b = b + "2";
    assert_eq!(b.len(), 7);
    assert_eq!(b, "1234522");
}

#[test]
fn remove() {
    let mut s = "ศไทย中华Việt Nam; foobar".to_cowstr();
    assert_eq!(s.remove(0), 'ศ');
    assert_eq!(s.len(), 33);
    assert_eq!(s, "ไทย中华Việt Nam; foobar");
    assert_eq!(s.remove(17), 'ệ');
    assert_eq!(s, "ไทย中华Vit Nam; foobar");
}

#[test]
#[should_panic]
fn remove_bad() {
    "ศ".to_cowstr().remove(1);
}

// PLANNED: still nightly with unstable Pattern API
// #[test]
// fn test_remove_matches() {
//     let mut s = "abc".to_cowstr();
//
//     s.remove_matches('b');
//     assert_eq!(s, "ac");
//     s.remove_matches('b');
//     assert_eq!(s, "ac");
//
//     let mut s = "abcb".to_cowstr();
//
//     s.remove_matches('b');
//     assert_eq!(s, "ac");
//
//     let mut s = "ศไทย中华Việt Nam; foobarศ".to_cowstr();
//     s.remove_matches('ศ');
//     assert_eq!(s, "ไทย中华Việt Nam; foobar");
//
//     let mut s = "".to_cowstr();
//     s.remove_matches("");
//     assert_eq!(s, "");
//
//     let mut s = "aaaaa".to_cowstr();
//     s.remove_matches('a');
//     assert_eq!(s, "");
// }

// PLANNED:
// #[test]
// fn test_retain() {
//     let mut s = String::from("α_β_γ");
//
//     s.retain(|_| true);
//     assert_eq!(s, "α_β_γ");
//
//     s.retain(|c| c != '_');
//     assert_eq!(s, "αβγ");
//
//     s.retain(|c| c != 'β');
//     assert_eq!(s, "αγ");
//
//     s.retain(|c| c == 'α');
//     assert_eq!(s, "α");
//
//     s.retain(|_| false);
//     assert_eq!(s, "");
//
//     let mut s = String::from("0è0");
//     let _ = panic::catch_unwind(panic::AssertUnwindSafe(|| {
//         let mut count = 0;
//         s.retain(|_| {
//             count += 1;
//             match count {
//                 1 => false,
//                 2 => true,
//                 _ => panic!(),
//             }
//         });
//     }));
//     assert!(std::str::from_utf8(s.as_bytes()).is_ok());
// }

#[test]
fn insert() {
    let mut s = "foobar".to_cowstr();
    s.insert(0, 'ệ');
    assert_eq!(s, "ệfoobar");
    s.insert(6, 'ย');
    assert_eq!(s, "ệfooยbar");
}

#[test]
#[should_panic]
fn insert_bad1() {
    "".to_cowstr().insert(1, 't');
}
#[test]
#[should_panic]
fn insert_bad2() {
    "ệ".to_cowstr().insert(1, 't');
}

#[test]
fn test_slicing() {
    let s = "foobar".to_cowstr();
    assert_eq!("foobar", &s[..]);
    assert_eq!("foo", &s[..3]);
    assert_eq!("bar", &s[3..]);
    assert_eq!("oob", &s[1..4]);
}

#[test]
fn test_simple_types() {
    assert_eq!(1.to_cowstr(), "1");
    assert_eq!((-1).to_cowstr(), "-1");
    assert_eq!(200.to_cowstr(), "200");
    assert_eq!(2.to_cowstr(), "2");
    assert_eq!(true.to_cowstr(), "true");
    assert_eq!(false.to_cowstr(), "false");
    assert_eq!(("hi".to_cowstr()).to_cowstr(), "hi");
}

#[test]
fn test_vectors() {
    let x: Vec<i32> = vec![];
    assert_eq!(format!("{x:?}"), "[]");
    assert_eq!(format!("{:?}", vec![1]), "[1]");
    assert_eq!(format!("{:?}", vec![1, 2, 3]), "[1, 2, 3]");
    assert!(format!("{:?}", vec![vec![], vec![1], vec![1, 1]]) == "[[], [1], [1, 1]]");
}

// PLANNED:
// #[test]
// fn test_from_iterator() {
//     let s = "ศไทย中华Việt Nam".to_cowstr();
//     let t = "ศไทย中华";
//     let u = "Việt Nam";
//
//     let a: String = s.chars().collect();
//     assert_eq!(s, a);
//
//     let mut b = t.to_cowstr();
//     b.extend(u.chars());
//     assert_eq!(s, b);
//
//     let c: String = [t, u].into_iter().collect();
//     assert_eq!(s, c);
//
//     let mut d = t.to_cowstr();
//     d.extend(vec![u]);
//     assert_eq!(s, d);
// }

// PLANNED:
// #[test]
// fn test_drain() {
//     let mut s = String::from("αβγ");
//     assert_eq!(s.drain(2..4).collect::<String>(), "β");
//     assert_eq!(s, "αγ");
//
//     let mut t = String::from("abcd");
//     t.drain(..0);
//     assert_eq!(t, "abcd");
//     t.drain(..1);
//     assert_eq!(t, "bcd");
//     t.drain(3..);
//     assert_eq!(t, "bcd");
//     t.drain(..);
//     assert_eq!(t, "");
// }

// NOTE: CowStr is generic on Ranges doesn't use RangeBounds, maybe fix this in future
// #[test]
// #[should_panic]
// fn test_drain_start_overflow() {
//     let mut s = String::from("abc");
//     s.drain((Excluded(usize::MAX), Included(0)));
// }
//
// #[test]
// #[should_panic]
// fn test_drain_end_overflow() {
//     let mut s = String::from("abc");
//     s.drain((Included(0), Included(usize::MAX)));
// }

#[test]
fn test_replace_range() {
    let mut s = "Hello, world!".to_owned();
    s.replace_range(7..12, "世界");
    assert_eq!(s, "Hello, 世界!");
}

#[test]
#[should_panic]
fn test_replace_range_char_boundary() {
    let mut s = "Hello, 世界!".to_owned();
    s.replace_range(..8, "");
}

#[test]
fn test_replace_range_inclusive_range() {
    let mut v = String::from("12345");
    v.replace_range(2..=3, "789");
    assert_eq!(v, "127895");
    v.replace_range(1..=2, "A");
    assert_eq!(v, "1A895");
}

#[test]
#[should_panic]
fn test_replace_range_out_of_bounds() {
    let mut s = String::from("12345");
    s.replace_range(5..6, "789");
}

#[test]
#[should_panic]
fn test_replace_range_inclusive_out_of_bounds() {
    let mut s = String::from("12345");
    s.replace_range(5..=5, "789");
}

// NOTE: CowStr is generic on Ranges doesn't use RangeBounds, maybe fix this in future
// #[test]
// #[should_panic]
// fn test_replace_range_start_overflow() {
//     let mut s = String::from("123");
//     s.replace_range((Excluded(usize::MAX), Included(0)), "");
// }
//
// #[test]
// #[should_panic]
// fn test_replace_range_end_overflow() {
//     let mut s = String::from("456");
//     s.replace_range((Included(0), Included(usize::MAX)), "");
// }

#[test]
fn test_replace_range_empty() {
    let mut s = String::from("12345");
    s.replace_range(1..2, "");
    assert_eq!(s, "1345");
}

#[test]
fn test_replace_range_unbounded() {
    let mut s = String::from("12345");
    s.replace_range(.., "");
    assert_eq!(s, "");
}

// NOTE: CowStr is generic on Ranges doesn't use RangeBounds, maybe fix this in future
// #[test]
// fn test_replace_range_evil_start_bound() {
//     struct EvilRange(Cell<bool>);
//
//     impl RangeBounds<usize> for EvilRange {
//         fn start_bound(&self) -> Bound<&usize> {
//             Bound::Included(if self.0.get() {
//                 &1
//             } else {
//                 self.0.set(true);
//                 &0
//             })
//         }
//         fn end_bound(&self) -> Bound<&usize> {
//             Bound::Unbounded
//         }
//     }
//
//     let mut s = String::from("🦀");
//     s.replace_range(EvilRange(Cell::new(false)), "");
//     assert_eq!(Ok(""), str::from_utf8(s.as_bytes()));
// }
//
// #[test]
// fn test_replace_range_evil_end_bound() {
//     struct EvilRange(Cell<bool>);
//
//     impl RangeBounds<usize> for EvilRange {
//         fn start_bound(&self) -> Bound<&usize> {
//             Bound::Included(&0)
//         }
//         fn end_bound(&self) -> Bound<&usize> {
//             Bound::Excluded(if self.0.get() {
//                 &3
//             } else {
//                 self.0.set(true);
//                 &4
//             })
//         }
//     }
//
//     let mut s = String::from("🦀");
//     s.replace_range(EvilRange(Cell::new(false)), "");
//     assert_eq!(Ok(""), str::from_utf8(s.as_bytes()));
// }

#[test]
fn test_extend_ref() {
    let mut a = "foo".to_cowstr();
    a.extend(&['b', 'a', 'r']);

    assert_eq!(&a, "foobar");
}

// NOTE: Not planned to support this as it would need reallocation
// #[test]
// fn test_into_boxed_str() {
//     let xs = String::from("hello my name is bob");
//     let ys = xs.into_boxed_str();
//     assert_eq!(&*ys, "hello my name is bob");
// }

// NOTE: CowStrs does not support reserve_exact(), just reserve()
// #[test]
// fn test_reserve_exact() {
//     // This is all the same as test_reserve
//
//     let mut s = String::new();
//     assert_eq!(s.capacity(), 0);
//
//     s.reserve_exact(2);
//     assert!(s.capacity() >= 2);
//
//     for _i in 0..16 {
//         s.push('0');
//     }
//
//     assert!(s.capacity() >= 16);
//     s.reserve_exact(16);
//     assert!(s.capacity() >= 32);
//
//     s.push('0');
//
//     s.reserve_exact(16);
//     assert!(s.capacity() >= 33)
// }
//
// #[test]
// #[cfg_attr(miri, ignore)] // Miri does not support signalling OOM
// #[cfg_attr(target_os = "android", ignore)] // Android used in CI has a broken dlmalloc
// #[cfg(feature = "nightly_assert_matches")]
// fn test_try_reserve() {
//     // These are the interesting cases:
//     // * exactly isize::MAX should never trigger a CapacityOverflow (can be OOM)
//     // * > isize::MAX should always fail
//     //    * On 16/32-bit should CapacityOverflow
//     //    * On 64-bit should OOM
//     // * overflow may trigger when adding `len` to `cap` (in number of elements)
//     // * overflow may trigger when multiplying `new_cap` by size_of::<T> (to get bytes)
//
//     const MAX_CAP: usize = isize::MAX as usize;
//     const MAX_USIZE: usize = usize::MAX;
//
//     {
//         // Note: basic stuff is checked by test_reserve
//         let mut empty_string: String = String::new();
//
//         // Check isize::MAX doesn't count as an overflow
//         if let Err(CapacityOverflow) = empty_string.try_reserve(MAX_CAP).map_err(|e| e.kind()) {
//             panic!("isize::MAX shouldn't trigger an overflow!");
//         }
//         // Play it again, frank! (just to be sure)
//         if let Err(CapacityOverflow) = empty_string.try_reserve(MAX_CAP).map_err(|e| e.kind()) {
//             panic!("isize::MAX shouldn't trigger an overflow!");
//         }
//
//         // Check isize::MAX + 1 does count as overflow
//         assert_matches!(
//             empty_string.try_reserve(MAX_CAP + 1).map_err(|e| e.kind()),
//             Err(CapacityOverflow),
//             "isize::MAX + 1 should trigger an overflow!"
//         );
//
//         // Check usize::MAX does count as overflow
//         assert_matches!(
//             empty_string.try_reserve(MAX_USIZE).map_err(|e| e.kind()),
//             Err(CapacityOverflow),
//             "usize::MAX should trigger an overflow!"
//         );
//     }
//
//     {
//         // Same basic idea, but with non-zero len
//         let mut ten_bytes: String = String::from("0123456789");
//
//         if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 10).map_err(|e| e.kind()) {
//             panic!("isize::MAX shouldn't trigger an overflow!");
//         }
//         if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 10).map_err(|e| e.kind()) {
//             panic!("isize::MAX shouldn't trigger an overflow!");
//         }
//
//         assert_matches!(
//             ten_bytes.try_reserve(MAX_CAP - 9).map_err(|e| e.kind()),
//             Err(CapacityOverflow),
//             "isize::MAX + 1 should trigger an overflow!"
//         );
//
//         // Should always overflow in the add-to-len
//         assert_matches!(
//             ten_bytes.try_reserve(MAX_USIZE).map_err(|e| e.kind()),
//             Err(CapacityOverflow),
//             "usize::MAX should trigger an overflow!"
//         );
//     }
// }
//
// #[test]
// #[cfg_attr(miri, ignore)] // Miri does not support signalling OOM
// #[cfg_attr(target_os = "android", ignore)] // Android used in CI has a broken dlmalloc
// #[cfg(feature = "nightly_assert_matches")]
// fn test_try_reserve_exact() {
//     // This is exactly the same as test_try_reserve with the method changed.
//     // See that test for comments.
//
//     const MAX_CAP: usize = isize::MAX as usize;
//     const MAX_USIZE: usize = usize::MAX;
//
//     {
//         let mut empty_string: String = String::new();
//
//         if let Err(CapacityOverflow) = empty_string
//             .try_reserve_exact(MAX_CAP)
//             .map_err(|e| e.kind())
//         {
//             panic!("isize::MAX shouldn't trigger an overflow!");
//         }
//         if let Err(CapacityOverflow) = empty_string
//             .try_reserve_exact(MAX_CAP)
//             .map_err(|e| e.kind())
//         {
//             panic!("isize::MAX shouldn't trigger an overflow!");
//         }
//
//         assert_matches!(
//             empty_string
//                 .try_reserve_exact(MAX_CAP + 1)
//                 .map_err(|e| e.kind()),
//             Err(CapacityOverflow),
//             "isize::MAX + 1 should trigger an overflow!"
//         );
//
//         assert_matches!(
//             empty_string
//                 .try_reserve_exact(MAX_USIZE)
//                 .map_err(|e| e.kind()),
//             Err(CapacityOverflow),
//             "usize::MAX should trigger an overflow!"
//         );
//     }
//
//     {
//         let mut ten_bytes: String = String::from("0123456789");
//
//         if let Err(CapacityOverflow) = ten_bytes
//             .try_reserve_exact(MAX_CAP - 10)
//             .map_err(|e| e.kind())
//         {
//             panic!("isize::MAX shouldn't trigger an overflow!");
//         }
//         if let Err(CapacityOverflow) = ten_bytes
//             .try_reserve_exact(MAX_CAP - 10)
//             .map_err(|e| e.kind())
//         {
//             panic!("isize::MAX shouldn't trigger an overflow!");
//         }
//
//         assert_matches!(
//             ten_bytes
//                 .try_reserve_exact(MAX_CAP - 9)
//                 .map_err(|e| e.kind()),
//             Err(CapacityOverflow),
//             "isize::MAX + 1 should trigger an overflow!"
//         );
//
//         assert_matches!(
//             ten_bytes.try_reserve_exact(MAX_USIZE).map_err(|e| e.kind()),
//             Err(CapacityOverflow),
//             "usize::MAX should trigger an overflow!"
//         );
//     }
// }

#[test]
fn test_from_char() {
    assert_eq!(String::from('a'), 'a'.to_cowstr());
    let s: String = 'x'.into();
    assert_eq!(s, 'x'.to_cowstr());
}

#[test]
fn test_str_concat() {
    let a: String = "hello".to_cowstr();
    let b: String = "world".to_cowstr();
    let s = format!("{a}{b}");
    assert_eq!(s.as_bytes()[9], b'd');
}