Update rand in the stdlib tests, and remove the getrandom feature from it

Author: thomcc

alloc/Cargo.toml

@@ -13,8 +13,8 @@ core = { path = "../core" }
 compiler_builtins = { version = "0.1.40", features = ['rustc-dep-of-std'] }
 
 [dev-dependencies]
-rand = "0.7"
-rand_xorshift = "0.2"
+rand = { version = "0.8.5", default-features = false, features = ["alloc"] }
+rand_xorshift = "0.3.0"
 
 [[test]]
 name = "collectionstests"

alloc/benches/slice.rs

@@ -1,6 +1,6 @@
 use std::{mem, ptr};
 
-use rand::distributions::{Alphanumeric, Standard};
+use rand::distributions::{Alphanumeric, DistString, Standard};
 use rand::Rng;
 use test::{black_box, Bencher};
 
@@ -218,7 +218,7 @@ fn gen_strings(len: usize) -> Vec<String> {
     let mut v = vec![];
     for _ in 0..len {
         let n = rng.gen::<usize>() % 20 + 1;
-        v.push((&mut rng).sample_iter(&Alphanumeric).take(n).collect());
+        v.push(Alphanumeric.sample_string(&mut rng, n));
     }
     v
 }

alloc/src/collections/binary_heap/tests.rs

@@ -465,7 +465,7 @@ fn test_retain() {
 #[test]
 #[cfg(not(target_os = "emscripten"))]
 fn panic_safe() {
-    use rand::{seq::SliceRandom, thread_rng};
+    use rand::seq::SliceRandom;
     use std::cmp;
     use std::panic::{self, AssertUnwindSafe};
     use std::sync::atomic::{AtomicUsize, Ordering};
@@ -490,7 +490,7 @@ fn panic_safe() {
             self.0.partial_cmp(&other.0)
         }
     }
-    let mut rng = thread_rng();
+    let mut rng = crate::test_helpers::test_rng();
     const DATASZ: usize = 32;
     // Miri is too slow
     let ntest = if cfg!(miri) { 1 } else { 10 };

alloc/src/collections/linked_list/tests.rs

@@ -5,7 +5,7 @@ use crate::vec::Vec;
 use std::panic::{catch_unwind, AssertUnwindSafe};
 use std::thread;
 
-use rand::{thread_rng, RngCore};
+use rand::RngCore;
 
 #[test]
 fn test_basic() {
@@ -481,12 +481,12 @@ fn test_split_off_2() {
     }
 }
 
-fn fuzz_test(sz: i32) {
+fn fuzz_test(sz: i32, rng: &mut impl RngCore) {
     let mut m: LinkedList<_> = LinkedList::new();
     let mut v = vec![];
     for i in 0..sz {
         check_links(&m);
-        let r: u8 = thread_rng().next_u32() as u8;
+        let r: u8 = rng.next_u32() as u8;
         match r % 6 {
             0 => {
                 m.pop_back();
@@ -521,11 +521,12 @@ fn fuzz_test(sz: i32) {
 
 #[test]
 fn test_fuzz() {
+    let mut rng = crate::test_helpers::test_rng();
     for _ in 0..25 {
-        fuzz_test(3);
-        fuzz_test(16);
+        fuzz_test(3, &mut rng);
+        fuzz_test(16, &mut rng);
         #[cfg(not(miri))] // Miri is too slow
-        fuzz_test(189);
+        fuzz_test(189, &mut rng);
     }
 }
 

alloc/src/lib.rs

@@ -192,6 +192,7 @@
 #![feature(unsized_fn_params)]
 #![feature(c_unwind)]
 #![feature(with_negative_coherence)]
+#![cfg_attr(test, feature(panic_update_hook))]
 //
 // Rustdoc features:
 #![feature(doc_cfg)]
@@ -255,3 +256,20 @@ pub mod vec;
 pub mod __export {
     pub use core::format_args;
 }
+
+#[cfg(test)]
+#[allow(dead_code)] // Not used in all configurations
+pub(crate) mod test_helpers {
+    /// Copied from `std::test_helpers::test_rng`, since these tests rely on the
+    /// seed not being the same for every RNG invocation too.
+    pub(crate) fn test_rng() -> rand_xorshift::XorShiftRng {
+        use std::hash::{BuildHasher, Hash, Hasher};
+        let mut hasher = std::collections::hash_map::RandomState::new().build_hasher();
+        std::panic::Location::caller().hash(&mut hasher);
+        let hc64 = hasher.finish();
+        let seed_vec =
+            hc64.to_le_bytes().into_iter().chain(0u8..8).collect::<crate::vec::Vec<u8>>();
+        let seed: [u8; 16] = seed_vec.as_slice().try_into().unwrap();
+        rand::SeedableRng::from_seed(seed)
+    }
+}

alloc/src/slice.rs

@@ -28,6 +28,9 @@ use crate::borrow::ToOwned;
 use crate::boxed::Box;
 use crate::vec::Vec;
 
+#[cfg(test)]
+mod tests;
+
 #[unstable(feature = "slice_range", issue = "76393")]
 pub use core::slice::range;
 #[unstable(feature = "array_chunks", issue = "74985")]