1 | //===-- Unittests for rand ------------------------------------------------===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | |
9 | #include "src/stdlib/rand.h" |
10 | #include "src/stdlib/srand.h" |
11 | #include "test/UnitTest/Test.h" |
12 | |
13 | #include <stddef.h> |
14 | |
15 | TEST(LlvmLibcRandTest, UnsetSeed) { |
16 | static int vals[1000]; |
17 | |
18 | for (size_t i = 0; i < 1000; ++i) { |
19 | int val = LIBC_NAMESPACE::rand(); |
20 | ASSERT_GE(val, 0); |
21 | ASSERT_LE(val, RAND_MAX); |
22 | vals[i] = val; |
23 | } |
24 | |
25 | // The C standard specifies that if 'srand' is never called it should behave |
26 | // as if 'srand' was called with a value of 1. If we seed the value with 1 we |
27 | // should get the same sequence as the unseeded version. |
28 | LIBC_NAMESPACE::srand(1); |
29 | for (size_t i = 0; i < 1000; ++i) |
30 | ASSERT_EQ(LIBC_NAMESPACE::rand(), vals[i]); |
31 | } |
32 | |
33 | TEST(LlvmLibcRandTest, SetSeed) { |
34 | const unsigned int SEED = 12344321; |
35 | LIBC_NAMESPACE::srand(SEED); |
36 | const size_t NUM_RESULTS = 10; |
37 | int results[NUM_RESULTS]; |
38 | for (size_t i = 0; i < NUM_RESULTS; ++i) { |
39 | results[i] = LIBC_NAMESPACE::rand(); |
40 | ASSERT_GE(results[i], 0); |
41 | ASSERT_LE(results[i], RAND_MAX); |
42 | } |
43 | |
44 | // If the seed is set to the same value, it should give the same sequence. |
45 | LIBC_NAMESPACE::srand(SEED); |
46 | |
47 | for (size_t i = 0; i < NUM_RESULTS; ++i) { |
48 | int val = LIBC_NAMESPACE::rand(); |
49 | EXPECT_EQ(results[i], val); |
50 | } |
51 | } |
52 | |