From 4fd2d2fc97e21efceab849576e544160fd5e3e3d Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Sat, 25 Feb 2017 12:16:58 -0800
Subject: Add a FastRandomContext::randrange and use it

---
 src/test/random_tests.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'src/test/random_tests.cpp')

diff --git a/src/test/random_tests.cpp b/src/test/random_tests.cpp
index 31b993cd3..859673422 100644
--- a/src/test/random_tests.cpp
+++ b/src/test/random_tests.cpp
@@ -35,4 +35,19 @@ BOOST_AUTO_TEST_CASE(fastrandom_tests)
     BOOST_CHECK(ctx3.rand64() != ctx4.rand64()); // extremely unlikely to be equal
 }
 
+BOOST_AUTO_TEST_CASE(fastrandom_randbits)
+{
+    FastRandomContext ctx1;
+    FastRandomContext ctx2;
+    for (int bits = 0; bits < 63; ++bits) {
+        for (int j = 0; j < 1000; ++j) {
+            uint64_t rangebits = ctx1.randbits(bits);
+            BOOST_CHECK_EQUAL(rangebits >> bits, 0);
+            uint64_t range = ((uint64_t)1) << bits | rangebits;
+            uint64_t rand = ctx2.randrange(range);
+            BOOST_CHECK(rand < range);
+        }
+    }
+}
+
 BOOST_AUTO_TEST_SUITE_END()
-- 
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