feat: add self-test for random number generation

1 files changed, 49 insertions, 0 deletions

diff --git a/na/test/test_random.cc b/na/test/test_random.cc
new file mode 100644
index 0000000..d546410
--- /dev/null
+++ b/na/test/test_random.cc
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2026 Richard Qin */
+
+#include <lume/selftest.h>
+#include <lume/random.h>
+#include <lume/kprintf.h>
+
+void selftest_random()
+{
+    /* Test 1: Basic 64-bit generation */
+    kprintf("[test] random: basic 64-bit generation ... ");
+    uint64 v1 = get_random_u64();
+    uint64 v2 = get_random_u64();
+    if (v1 == v2) {
+        kernel_panic("random: two consecutive generations were identical!");
+    }
+    kprintf("PASS\n");
+
+    /* Test 2: Basic 32-bit generation */
+    kprintf("[test] random: basic 32-bit generation ... ");
+    uint32 v3 = get_random_u32();
+    uint32 v4 = get_random_u32();
+    if (v3 == v4) {
+        kernel_panic("random: two consecutive 32-bit generations were identical!");
+    }
+    kprintf("PASS\n");
+
+    /* Test 3: Byte generation */
+    kprintf("[test] random: byte generation ... ");
+    uint8 buf1[16];
+    uint8 buf2[16];
+    get_random_bytes(buf1, sizeof(buf1));
+    get_random_bytes(buf2, sizeof(buf2));
+    
+    bool all_zero1 = true;
+    bool all_zero2 = true;
+    bool same = true;
+
+    for (int i = 0; i < 16; i++) {
+        if (buf1[i] != 0) all_zero1 = false;
+        if (buf2[i] != 0) all_zero2 = false;
+        if (buf1[i] != buf2[i]) same = false;
+    }
+
+    if (all_zero1 || all_zero2 || same) {
+        kernel_panic("random: byte generation statistical failure!");
+    }
+    kprintf("PASS\n");
+}