fixes #1083 Random number improvements

1 files changed, 51 insertions, 26 deletions

diff --git a/tests/platform.c b/tests/platform.c
index 7546fa7f..fc9eb210 100644
--- a/tests/platform.c
+++ b/tests/platform.c
@@ -66,10 +66,10 @@ test_clock(void)
 	TEST_CHECK(usdelta >= 200);
 	TEST_CHECK(usdelta < 500); // increased tolerance for CIs
 	if (msdelta > usdelta) {
-                TEST_CHECK((msdelta - usdelta) < 50);
+		TEST_CHECK((msdelta - usdelta) < 50);
 	} else {
-                TEST_CHECK((usdelta - msdelta) < 50);
-        }
+		TEST_CHECK((usdelta - msdelta) < 50);
+	}
 }
 
 void
@@ -108,40 +108,65 @@ test_thread(void)
 	nng_thread_destroy(thr);
 	TEST_CHECK(aa.cnt == 1);
 
-        nng_cv_free(aa.cv);
+	nng_cv_free(aa.cv);
 	nng_mtx_free(aa.mx);
 }
 
 void
 test_condvar(void)
 {
-        nng_thread *  thr;
-        int           rv;
-        struct addarg aa;
-
-        TEST_CHECK(nng_mtx_alloc(&aa.mx) == 0);
-        TEST_CHECK(nng_cv_alloc(&aa.cv, aa.mx) == 0);
-        aa.cnt = 0;
-
-        TEST_CHECK((rv = nng_thread_create(&thr, add, &aa)) == 0);
-
-        nng_mtx_lock(aa.mx);
-        while (aa.cnt == 0) {
-                nng_cv_wait(aa.cv);
-        }
-        nng_mtx_unlock(aa.mx);
-        nng_thread_destroy(thr);
-        TEST_CHECK(aa.cnt == 1);
-
-        nng_cv_free(aa.cv);
-        nng_mtx_free(aa.mx);
+	nng_thread *  thr;
+	int           rv;
+	struct addarg aa;
+
+	TEST_CHECK(nng_mtx_alloc(&aa.mx) == 0);
+	TEST_CHECK(nng_cv_alloc(&aa.cv, aa.mx) == 0);
+	aa.cnt = 0;
+
+	TEST_CHECK((rv = nng_thread_create(&thr, add, &aa)) == 0);
+
+	nng_mtx_lock(aa.mx);
+	while (aa.cnt == 0) {
+		nng_cv_wait(aa.cv);
+	}
+	nng_mtx_unlock(aa.mx);
+	nng_thread_destroy(thr);
+	TEST_CHECK(aa.cnt == 1);
+
+	nng_cv_free(aa.cv);
+	nng_mtx_free(aa.mx);
+}
+
+void
+test_random(void)
+{
+	int      same = 0;
+	uint32_t values[1000];
+
+	for (int i = 0; i < 1000; i++) {
+		values[i] = nng_random();
+	}
+	for (int i = 0; i < 1000; i++) {
+		for (int j = 0; j < i; j++) {
+			if (values[j] == values[i]) {
+				same++;
+			}
+		}
+	}
+
+	// 1% reproduction is *highly* unlikely.
+	// There are 4 billion possible options, we are only looking at
+	// 1000 of them.  In general, it would be an extreme outlier
+	// to see more than 2 repeats, unless you RNG is biased.
+	TEST_CHECK_(same < 5, "fewer than 5 in 1000 repeats: %d", same);
 }
 
 TEST_LIST = {
 	{ "sleep", test_sleep },
 	{ "clock", test_clock },
 	{ "mutex", test_mutex },
-        { "thread", test_thread },
-        { "condvar", test_condvar },
+	{ "thread", test_thread },
+	{ "condvar", test_condvar },
+	{ "random", test_random },
 	{ NULL, NULL },
 };