scc

commit f31dacb5f419d4e082230bd8366c97585e5c9b16
parent 2b616739bf590b1f3cbf3740e5b60e1b56e5edd2
Author: Roberto E. Vargas Caballero <k0ga@shike2.net>
Date:   Thu, 30 Apr 2026 23:51:30 +0200

tests/libc: Add 0090-rand

Diffstat:
M
tests/libc/execute/.gitignore
 | 
1
+
A
tests/libc/execute/0090-rand.c
 | 
83
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M
tests/libc/execute/libc-tests.lst
 | 
1
+

3 files changed, 85 insertions(+), 0 deletions(-)
diff --git a/tests/libc/execute/.gitignore b/tests/libc/execute/.gitignore
@@ -88,3 +88,4 @@ test.log
 0087-stroll
 0088-stroul
 0089-stroull
+0090-rand
diff --git a/tests/libc/execute/0090-rand.c b/tests/libc/execute/0090-rand.c
@@ -0,0 +1,83 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+
+/*
+output:
+testing
+test1
+test2
+done
+end:
+*/
+
+#define NR_BINS 64
+#define NR_DOTS 16000
+#define CRITLVL 82.53
+
+static void
+test1(void)
+{
+	int max, min, i, n;
+	float chi, d;
+	static int bins[NR_BINS];
+
+	puts("test1");
+	for (i = 0; i < NR_DOTS; ++i) {
+		n = rand();
+		assert(n >= 0 && n <= RAND_MAX);
+		bins[n & NR_BINS-1]++;
+	}
+
+	chi = 0;
+	for (i = 0; i < NR_BINS; ++i) {
+		d = bins[i] - (float) NR_DOTS / NR_BINS;
+		d *= d;
+		d /= (float) NR_DOTS / NR_BINS;
+		chi += d;
+	}
+
+	assert(chi <= CRITLVL);
+}
+
+#undef NR_DOTS
+
+#define NR_SEEDS 10
+#define NR_DOTS  32
+
+static void
+test2(void)
+{
+	int i, j, dots[NR_SEEDS][NR_DOTS];
+	unsigned seeds[NR_SEEDS];
+
+	puts("test2");
+	for (i = 0; i < NR_SEEDS; i++)
+		seeds[i] = rand();
+
+	for (i = 0; i < NR_SEEDS; i++) {
+		srand(seeds[i]);
+
+		for (j = 0; j < NR_DOTS; ++j)
+			dots[i][j] = rand();
+	}
+
+	for (i = 0; i < NR_SEEDS; i++) {
+		srand(seeds[i]);
+
+		for (j = 0; j < NR_DOTS; ++j)
+			assert(dots[i][j] == rand());
+	}
+}
+
+int
+main(void)
+{
+	puts("testing");
+	test1();
+	test2();
+	puts("done");
+
+	return 0;
+}
diff --git a/tests/libc/execute/libc-tests.lst b/tests/libc/execute/libc-tests.lst
@@ -86,3 +86,4 @@
 0087-stroll
 0088-stroul
 0089-stroull
+0090-rand