From ed2bd527e86581ea0f65903cc9bf690a0f84e3a1 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Tue, 2 Jul 2019 06:34:37 -0400
Subject: [PATCH] use a fixed seed

---
 src/lru.rs      | 15 +++++----------
 src/lru/test.rs |  3 +--
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/src/lru.rs b/src/lru.rs
index e6c29e8a..22a10e97 100644
--- a/src/lru.rs
+++ b/src/lru.rs
@@ -1,6 +1,5 @@
 use parking_lot::Mutex;
 use rand::rngs::SmallRng;
-use rand::FromEntropy;
 use rand::Rng;
 use rand::SeedableRng;
 use std::fmt::Debug;
@@ -58,16 +57,17 @@ where
     }
 }
 
+// We always use a fixed seed for our randomness so that we have
+// predictable results.
+const LRU_SEED: &str = "Hello, Rustaceans";
+
 impl<Node> Lru<Node>
 where
     Node: LruNode,
 {
     /// Creates a new LRU list where LRU caching is disabled.
     pub fn new() -> Self {
-        Lru {
-            green_zone: AtomicUsize::new(0),
-            data: Mutex::new(LruData::new()),
-        }
+        Self::with_seed(LRU_SEED)
     }
 
     #[cfg_attr(not(test), allow(dead_code))]
@@ -137,11 +137,6 @@ impl<Node> LruData<Node>
 where
     Node: LruNode,
 {
-    fn new() -> Self {
-        Self::with_rng(SmallRng::from_entropy())
-    }
-
-    #[cfg_attr(not(test), allow(dead_code))]
     fn with_seed(seed_str: &str) -> Self {
         Self::with_rng(rng_with_seed(seed_str))
     }
diff --git a/src/lru/test.rs b/src/lru/test.rs
index 8f48d5cb..d77903a5 100644
--- a/src/lru/test.rs
+++ b/src/lru/test.rs
@@ -25,7 +25,6 @@ impl LruNode for TestNode {
     }
 }
 
-const LRU_SEED: &str = "Hello, Rustaceans";
 const PICK_SEED: &str = "Wippity WIP";
 
 /// Randomly requests nodes and compares the performance of a
@@ -48,7 +47,7 @@ fn compare(
     // it. When the capacity is exceed, we can pop the oldest.
     let mut oracle = LinkedHashMap::new();
 
-    let lru = Lru::with_seed(LRU_SEED);
+    let lru = Lru::with_seed(super::LRU_SEED);
     lru.set_lru_capacity(capacity);
 
     let nodes: Vec<_> = (0..num_nodes).map(|i| TestNode::new(i)).collect();