From 63f615c6c092fcc8c222e3906d4cc2796390da80 Mon Sep 17 00:00:00 2001
From: Mitya Selivanov <0x7fffff@guattari.ru>
Date: Tue, 16 Aug 2022 01:44:55 +0400
Subject: Mersenne Twister 64

---
 source/test/unittests/CMakeLists.txt             |  3 ++-
 source/test/unittests/mersenne_twister_64.test.c | 33 ++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 source/test/unittests/mersenne_twister_64.test.c

(limited to 'source/test')

diff --git a/source/test/unittests/CMakeLists.txt b/source/test/unittests/CMakeLists.txt
index 3dda690..5ec950d 100644
--- a/source/test/unittests/CMakeLists.txt
+++ b/source/test/unittests/CMakeLists.txt
@@ -3,4 +3,5 @@ target_sources(
     PRIVATE
       async_function.test.c test_duration.test.c main.test.c
       string_ref.test.c atomic.test.c array_ref.test.c input_stream.test.c
-      lower_bound.test.c input_buffer.test.c dynamic_array.test.c)
+      lower_bound.test.c mersenne_twister_64.test.c input_buffer.test.c
+      dynamic_array.test.c)
diff --git a/source/test/unittests/mersenne_twister_64.test.c b/source/test/unittests/mersenne_twister_64.test.c
new file mode 100644
index 0000000..37c82b4
--- /dev/null
+++ b/source/test/unittests/mersenne_twister_64.test.c
@@ -0,0 +1,33 @@
+#include "../../kit/mersenne_twister_64.h"
+
+#define TEST_FILE mersenne_twister_64
+#include "../../kit_test/test.h"
+
+enum { SIZE = 1000 };
+
+TEST("mt64 same seeds") {
+  uint64_t seed = mt64_seed();
+
+  mt64_state_t foo, bar;
+  mt64_init(&foo, seed);
+  mt64_init(&bar, seed);
+
+  int ok = 1;
+  for (ptrdiff_t i = 0; i < SIZE; i++)
+    ok = ok && mt64_generate(&foo) == mt64_generate(&bar);
+
+  REQUIRE(ok);
+}
+
+TEST("mt64 different seeds") {
+  mt64_state_t foo, bar;
+  mt64_init(&foo, 42);
+  mt64_init(&bar, 4242424242);
+
+  ptrdiff_t difference_count = 0;
+  for (ptrdiff_t i = 0; i < SIZE; i++)
+    if (mt64_generate(&foo) != mt64_generate(&bar))
+      difference_count++;
+
+  REQUIRE(difference_count > SIZE / 2);
+}
-- 
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