bytemuck/tests/std_tests.rs
Julien Cretin fd27a5b018
Add from_box_bytes and box_bytes_of with BoxBytes type (#211)
* Add from_box_bytes and box_bytes_of with BoxBytes type

* Apply suggestions from code review

Co-authored-by: zachs18 <8355914+zachs18@users.noreply.github.com>

* Add into_raw_parts

* Add tests

* Rename from_parts to from_raw_parts

---------

Co-authored-by: zachs18 <8355914+zachs18@users.noreply.github.com>
2023-10-19 22:50:33 -06:00

107 lines
3.0 KiB
Rust

#![allow(clippy::uninlined_format_args)]
//! The integration tests seem to always have `std` linked, so things that would
//! depend on that can go here.
use bytemuck::*;
use core::num::NonZeroU8;
#[test]
fn test_transparent_vtabled() {
use core::fmt::Display;
#[repr(transparent)]
struct DisplayTraitObj(dyn Display);
unsafe impl TransparentWrapper<dyn Display> for DisplayTraitObj {}
impl Display for DisplayTraitObj {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
self.0.fmt(f)
}
}
let v = DisplayTraitObj::wrap_ref(&5i32);
let s = format!("{}", v);
assert_eq!(s, "5");
let mut x = 100i32;
let v_mut = DisplayTraitObj::wrap_mut(&mut x);
let s = format!("{}", v_mut);
assert_eq!(s, "100");
}
#[test]
#[cfg(feature = "extern_crate_alloc")]
fn test_large_box_alloc() {
type SuperPage = [[u8; 4096]; 4096];
let _: Box<SuperPage> = try_zeroed_box().unwrap();
}
#[test]
#[cfg(feature = "extern_crate_alloc")]
fn test_zero_sized_box_alloc() {
#[repr(align(4096))]
struct Empty;
unsafe impl Zeroable for Empty {}
let _: Box<Empty> = try_zeroed_box().unwrap();
}
#[test]
#[cfg(feature = "extern_crate_alloc")]
fn test_try_from_box_bytes() {
// Different layout: target alignment is greater than source alignment.
assert_eq!(
try_from_box_bytes::<u32>(Box::new([0u8; 4]).into()).map_err(|(x, _)| x),
Err(PodCastError::AlignmentMismatch)
);
// Different layout: target alignment is less than source alignment.
assert_eq!(
try_from_box_bytes::<u32>(Box::new(0u64).into()).map_err(|(x, _)| x),
Err(PodCastError::AlignmentMismatch)
);
// Different layout: target size is greater than source size.
assert_eq!(
try_from_box_bytes::<[u32; 2]>(Box::new(0u32).into()).map_err(|(x, _)| x),
Err(PodCastError::SizeMismatch)
);
// Different layout: target size is less than source size.
assert_eq!(
try_from_box_bytes::<u32>(Box::new([0u32; 2]).into()).map_err(|(x, _)| x),
Err(PodCastError::SizeMismatch)
);
// Round trip: alignment is equal to size.
assert_eq!(*from_box_bytes::<u32>(Box::new(1000u32).into()), 1000u32);
// Round trip: alignment is divider of size.
assert_eq!(&*from_box_bytes::<[u8; 5]>(Box::new(*b"hello").into()), b"hello");
// It's ok for T to have uninitialized bytes.
#[cfg(feature = "derive")]
{
#[derive(Debug, Copy, Clone, PartialEq, Eq, AnyBitPattern)]
struct Foo(u8, u16);
assert_eq!(
*from_box_bytes::<Foo>(Box::new([0xc5c5u16; 2]).into()),
Foo(0xc5u8, 0xc5c5u16)
);
}
}
#[test]
#[cfg(feature = "extern_crate_alloc")]
fn test_box_bytes_of() {
assert_eq!(&*box_bytes_of(Box::new(*b"hello")), b"hello");
#[cfg(target_endian = "big")]
assert_eq!(&*box_bytes_of(Box::new(0x12345678)), b"\x12\x34\x56\x78");
#[cfg(target_endian = "little")]
assert_eq!(&*box_bytes_of(Box::new(0x12345678)), b"\x78\x56\x34\x12");
// It's ok for T to have invalid bit patterns.
assert_eq!(&*box_bytes_of(Box::new(NonZeroU8::new(0xc5))), b"\xc5");
}