Build: share one test RNG across randomized tests (#1868)

crates/socket-patch-core/src/crawlers/cargo_crawler.rs

@@ -1394,7 +1394,8 @@ version = "fake"
     mod equivalence {
         use super::super::oracle::LegacyCargoCrawler;
         use super::*;
-        use crate::crawlers::oracle_support::{mkdir, rows, symlink, write, PermGuard, Rng};
+        use crate::crawlers::oracle_support::{mkdir, rows, symlink, write, PermGuard};
+        use crate::test_rng::Rng;
 
         const NAMES: &[&str] = &["serde", "serde-json", "sha-1", "tokio", "dup", "a_b"];
         const VERSIONS: &[&str] = &["1.0.0", "1.0.0-rc.1", "0.2.3", "5", "1.0.0+build"];

crates/socket-patch-core/src/crawlers/composer_crawler.rs

@@ -2376,7 +2376,8 @@ mod tests {
     mod equivalence {
         use super::super::oracle::LegacyComposerCrawler;
         use super::*;
-        use crate::crawlers::oracle_support::{map_rows, mkdir, rows, symlink, write, Rng};
+        use crate::crawlers::oracle_support::{map_rows, mkdir, rows, symlink, write};
+        use crate::test_rng::Rng;
 
         const NAMES: &[&str] = &[
             "monolog/monolog",

crates/socket-patch-core/src/crawlers/go_crawler.rs

@@ -1696,9 +1696,8 @@ mod tests {
     mod equivalence {
         use super::super::oracle::LegacyGoCrawler;
         use super::*;
-        use crate::crawlers::oracle_support::{
-            map_rows, mkdir, rows, symlink, write, PermGuard, Rng,
-        };
+        use crate::crawlers::oracle_support::{map_rows, mkdir, rows, symlink, write, PermGuard};
+        use crate::test_rng::Rng;
 
         const NAMES: &[&str] = &[
             "github.com",

crates/socket-patch-core/src/crawlers/maven_crawler.rs

@@ -2909,8 +2909,9 @@ mod tests {
         use super::super::oracle::LegacyMavenCrawler;
         use super::*;
         use crate::crawlers::oracle_support::{
-            mkdir, rows, symlink, write, write_bytes, PermGuard, Rng,
+            mkdir, rows, symlink, write, write_bytes, PermGuard,
         };
+        use crate::test_rng::Rng;
 
         const GROUPS: &[&str] = &["org/apache/commons", "com/google/guava", "io/netty"];
         const ARTIFACTS: &[&str] = &["commons-lang3", "guava", "netty-all", "dup"];

crates/socket-patch-core/src/crawlers/nuget_crawler.rs

@@ -2096,9 +2096,8 @@ mod tests {
     mod equivalence {
         use super::super::oracle::LegacyNuGetCrawler;
         use super::*;
-        use crate::crawlers::oracle_support::{
-            map_rows, mkdir, rows, symlink, write, PermGuard, Rng,
-        };
+        use crate::crawlers::oracle_support::{map_rows, mkdir, rows, symlink, write, PermGuard};
+        use crate::test_rng::Rng;
 
         const IDS: &[&str] = &["Newtonsoft.Json", "xunit", "System.Text.Json", "Dup", "dup"];
         const VERSIONS: &[&str] = &["13.0.3", "2.0.0-RC1", "8.0.0", "1.0.0"];

crates/socket-patch-core/src/crawlers/oracle_support.rs

@@ -7,36 +7,6 @@ use std::path::{Path, PathBuf};
 
 use super::types::CrawledPackage;
 
-/// Deterministic xorshift64* generator (no `rand` dependency).
-pub(crate) struct Rng(u64);
-
-impl Rng {
-    pub(crate) fn new(seed: u64) -> Self {
-        Self(seed.wrapping_mul(0x9E37_79B9_7F4A_7C15) | 1)
-    }
-
-    pub(crate) fn next(&mut self) -> u64 {
-        let mut x = self.0;
-        x ^= x >> 12;
-        x ^= x << 25;
-        x ^= x >> 27;
-        self.0 = x;
-        x.wrapping_mul(0x2545_F491_4F6C_DD1D)
-    }
-
-    pub(crate) fn below(&mut self, n: usize) -> usize {
-        (self.next() % n as u64) as usize
-    }
-
-    pub(crate) fn chance(&mut self, pct: usize) -> bool {
-        self.below(100) < pct
-    }
-
-    pub(crate) fn pick<'a>(&mut self, items: &[&'a str]) -> &'a str {
-        items[self.below(items.len())]
-    }
-}
-
 /// Restores permissions a generator stripped before the tempdir is removed
 /// (declare it AFTER the tempdir so it drops first). Only Unix strips
 /// permissions; everywhere else the plan is recorded and ignored.

crates/socket-patch-core/src/crawlers/python_crawler.rs

@@ -7946,8 +7946,9 @@ G=
         use super::super::oracle::{self, LegacyPythonCrawler};
         use super::*;
         use crate::crawlers::oracle_support::{
-            fifo, map_rows, mkdir, rows, symlink, write, write_bytes, PermGuard, Rng,
+            fifo, map_rows, mkdir, rows, symlink, write, write_bytes, PermGuard,
         };
+        use crate::test_rng::Rng;
 
         const NAMES: &[&str] = &["requests", "Flask_Cors", "zope.interface", "dup", "Dup"];
         const VERSIONS: &[&str] = &["1.0", "2.31.0", "1.0+local", "3.0a1"];

crates/socket-patch-core/src/crawlers/ruby_crawler.rs

@@ -6241,7 +6241,8 @@ mod tests {
 
     #[tokio::test]
     async fn find_each_by_purl_matches_per_purl_find_by_purls() {
-        use crate::crawlers::oracle_support::{mkdir, symlink, write, PermGuard, Rng};
+        use crate::crawlers::oracle_support::{mkdir, symlink, write, PermGuard};
+        use crate::test_rng::Rng;
 
         const GEMS: &[&str] = &["rails", "nokogiri", "rack", "rails-html"];
         const VERSIONS: &[&str] = &["7.1.0", "1.16.5", "3.0.0"];

crates/socket-patch-core/src/patch/copy_tree.rs

@@ -198,6 +198,7 @@ pub async fn remove_tree(dir: &Path) -> std::io::Result<()> {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::test_rng::Rng;
     use std::fs;
 
     #[cfg(unix)]
@@ -234,23 +235,6 @@ mod tests {
             .collect()
     }
 
-    /// Deterministic xorshift64* — no `rand` dev-dependency.
-    struct Rng(u64);
-
-    impl Rng {
-        fn next(&mut self) -> u64 {
-            let mut x = self.0;
-            x ^= x >> 12;
-            x ^= x << 25;
-            x ^= x >> 27;
-            self.0 = x;
-            x.wrapping_mul(0x2545_F491_4F6C_DD1D)
-        }
-        fn below(&mut self, n: usize) -> usize {
-            (self.next() % n as u64) as usize
-        }
-    }
-
     const SKIP: &str = ".cargo-checksum.json";
 
     /// A random tree under `dir`: nested and empty dirs, files (some

crates/socket-patch-core/src/patch/redirect/pnpm_equivalence_tests.rs

@@ -426,7 +426,7 @@ fn indexed_pnpm_rewrite_matches_golden_on_random_lock_sets() {
     // instead of quietly testing only the plain rewrite path.
     let mut outcomes: std::collections::BTreeSet<String> = std::collections::BTreeSet::new();
     for seed in 1..=300u64 {
-        let mut rng = Rng(seed.wrapping_mul(0x9E37_79B9_7F4A_7C15) | 1);
+        let mut rng = Rng::new(seed);
         let lock_count = 1 + rng.below(3);
         let mut files = BTreeMap::new();
         let mut all: Vec<Pkg> = Vec::new();

crates/socket-patch-core/src/vendor/go_mod_edit.rs

@@ -2543,13 +2543,8 @@ replace (
     /// Random go.mod-grammar text: directive keywords (and near misses),
     /// block opens/closes (balanced or not), comments, blank lines, CRLF.
     fn random_go_mod(seed: u64) -> String {
-        let mut x = seed.wrapping_mul(0x9E37_79B9_7F4A_7C15) | 1;
-        let mut next = move |n: usize| {
-            x ^= x >> 12;
-            x ^= x << 25;
-            x ^= x >> 27;
-            (x.wrapping_mul(0x2545_F491_4F6C_DD1D) % n as u64) as usize
-        };
+        let mut rng = crate::test_rng::Rng::new(seed);
+        let mut next = move |n: usize| rng.below(n);
         const PIECES: &[&str] = &[
             "replace",
             "require",

crates/socket-patch-core/src/vendor/go_sum_edit.rs

@@ -777,13 +777,8 @@ mod tests {
     #[test]
     fn lines_form_matches_the_text_form_step_by_step() {
         for seed in 1..=3000u64 {
-            let mut x = seed.wrapping_mul(0x9E37_79B9_7F4A_7C15) | 1;
-            let mut rng = move |n: usize| {
-                x ^= x >> 12;
-                x ^= x << 25;
-                x ^= x >> 27;
-                (x.wrapping_mul(0x2545_F491_4F6C_DD1D) % n as u64) as usize
-            };
+            let mut r = crate::test_rng::Rng::new(seed);
+            let mut rng = move |n: usize| r.below(n);
             let start = random_go_sum(&mut rng);
             let mut text = start.clone();
             let mut editor = GoSumEditor::new(start.clone());

crates/socket-patch-core/src/vex/verify.rs

@@ -2597,7 +2597,8 @@ mod tests {
 
     #[tokio::test]
     async fn judge_installed_record_matches_verify_and_evidence_scan() {
-        use crate::crawlers::oracle_support::{fifo, mkdir, write, Rng};
+        use crate::crawlers::oracle_support::{fifo, mkdir, write};
+        use crate::test_rng::Rng;
 
         let patched = compute_git_sha256_from_bytes(b"patched");
         let upstream = compute_git_sha256_from_bytes(b"upstream");