1 files changed, 90 insertions, 0 deletions
diff --git a/test/unittests/unit_rand.c b/test/unittests/unit_rand.c
new file mode 100644
index 00000000..1ad02a80
--- /dev/null
+++ b/test/unittests/unit_rand.c
@@ -0,0 +1,90 @@
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <assert.h>
+#include <cmocka.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+/* cmocka < 1.0 didn't support these features we need */
+#ifndef assert_ptr_equal
+#define assert_ptr_equal(a, b) \
+    _assert_int_equal(cast_ptr_to_largest_integral_type(a), \
+                      cast_ptr_to_largest_integral_type(b), \
+                      __FILE__, __LINE__)
+#define CMUnitTest UnitTest
+#define cmocka_unit_test unit_test
+#define cmocka_run_group_tests(t, setup, teardown) run_tests(t)
+#endif
+
+
+extern void mock_assert(const int result, const char* const expression,
+                        const char * const file, const int line);
+#undef assert
+#define assert(expression) \
+    mock_assert((int)(expression), #expression, __FILE__, __LINE__);
+
+#include "afl-fuzz.h"
+
+/* remap exit -> assert, then use cmocka's mock_assert
+    (compile with `--wrap=exit`) */
+extern void exit(int status);
+extern void __real_exit(int status);
+//void __wrap_exit(int status);
+void __wrap_exit(int status) {
+    (void)status;
+    assert(0);
+}
+
+/* ignore all printfs */
+#undef printf
+extern int printf(const char *format, ...);
+extern int __real_printf(const char *format, ...);
+int __wrap_printf(const char *format, ...);
+int __wrap_printf(const char *format, ...) {
+    (void)format;
+    return 1;
+}
+
+/* Rand with 0 seed would broke in the past */
+static void test_rand_0(void **state) {
+    (void)state;
+
+    afl_state_t afl = {0};
+    rand_set_seed(&afl, 0);
+
+    /* give this one chance to retry */
+    assert_int_not_equal(
+        (rand_next(&afl) != rand_next(&afl)
+            || rand_next(&afl) != rand_next(&afl))
+            , 0);
+
+}
+
+static void test_rand_below(void **state) {
+    (void)state;
+
+    afl_state_t afl = {0};
+    rand_set_seed(&afl, 1337);
+
+    afl.fsrv.dev_urandom_fd = open("/dev/urandom", O_RDONLY);
+
+    assert(!(rand_below(&afl, 9000) > 9000));
+    assert_int_equal(rand_below(&afl, 1), 0);
+
+}
+
+int main(int argc, char **argv) {
+    (void)argc;
+    (void)argv;
+
+    const struct CMUnitTest tests[] = {
+        cmocka_unit_test(test_rand_0),
+        cmocka_unit_test(test_rand_below)
+    };
+
+    //return cmocka_run_group_tests (tests, setup, teardown);
+    __real_exit( cmocka_run_group_tests (tests, NULL, NULL) );
+
+    // fake return for dumb compilers
+    return 0;
+}