#[unstable(feature = "sealed", issue = "none")]
pub trait Sealed {}
}
+
+#[cfg(test)]
+#[allow(dead_code)] // Not used in all configurations.
+pub(crate) mod test_helpers {
+ /// Test-only replacement for `rand::thread_rng()`, which is unusable for
+ /// us, as we want to allow running stdlib tests on tier-3 targets which may
+ /// not have `getrandom` support.
+ ///
+ /// Does a bit of a song and dance to ensure that the seed is different on
+ /// each call (as some tests sadly rely on this), but doesn't try that hard.
+ ///
+ /// This is duplicated in the `core`, `alloc` test suites (as well as
+ /// `std`'s integration tests), but figuring out a mechanism to share these
+ /// seems far more painful than copy-pasting a 7 line function a couple
+ /// times, given that even under a perma-unstable feature, I don't think we
+ /// want to expose types from `rand` from `std`.
+ #[track_caller]
+ pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
+ use core::hash::{BuildHasher, Hash, Hasher};
+ let mut hasher = crate::collections::hash_map::RandomState::new().build_hasher();
+ core::panic::Location::caller().hash(&mut hasher);
+ let hc64 = hasher.finish();
+ let seed_vec = hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<Vec<u8>>();
+ let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
+ rand::SeedableRng::from_seed(seed)
+ }
+}