From f0b21e3182a56f5424ae2924ea96f49769b0b318 Mon Sep 17 00:00:00 2001
From: David Turner <david.turner@elastic.co>
Date: Mon, 18 Dec 2017 09:57:40 +0000
Subject: [PATCH] Make randomNonNegativeLong() draw from a uniform distribution
 (#27856)

Currently randomNonNegativeLong() returns 0 half as often as any positive long,
but random number generators are typically expected to return
uniformly-distributed values unless otherwise specified. This fixes this issue
by mapping Long.MIN_VALUE directly onto 0 rather than resampling.
---
 .../main/java/org/elasticsearch/test/ESTestCase.java   | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java b/test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java
index 84e750f6e28..d2712e268ad 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/ESTestCase.java
@@ -509,12 +509,12 @@ public abstract class ESTestCase extends LuceneTestCase {
         return random().nextInt();
     }
 
+    /**
+     * @return a <code>long</code> between <code>0</code> and <code>Long.MAX_VALUE</code> (inclusive) chosen uniformly at random.
+     */
     public static long randomNonNegativeLong() {
-        long randomLong;
-        do {
-            randomLong = randomLong();
-        } while (randomLong == Long.MIN_VALUE);
-        return Math.abs(randomLong);
+        long randomLong = randomLong();
+        return randomLong == Long.MIN_VALUE ? 0 : Math.abs(randomLong);
     }
 
     public static float randomFloat() {