1//===-- Unittests for strncat ---------------------------------------------===//
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/string/strncat.h"
10#include "test/UnitTest/Test.h"
11
12TEST(LlvmLibcStrNCatTest, EmptyDest) {
13 const char *abc = "abc";
14 char dest[4];
15
16 dest[0] = '\0';
17
18 // Start by copying nothing
19 char *result = LIBC_NAMESPACE::strncat(dest, abc, 0);
20 ASSERT_EQ(dest, result);
21 ASSERT_EQ(dest[0], '\0');
22
23 // Then copy part of it.
24 result = LIBC_NAMESPACE::strncat(dest, abc, 1);
25 ASSERT_EQ(dest, result);
26 ASSERT_STREQ(dest, "a");
27
28 // Reset for the last test.
29 dest[0] = '\0';
30
31 // Then copy all of it.
32 result = LIBC_NAMESPACE::strncat(dest, abc, 3);
33 ASSERT_EQ(dest, result);
34 ASSERT_STREQ(dest, result);
35 ASSERT_STREQ(dest, abc);
36}
37
38TEST(LlvmLibcStrNCatTest, NonEmptyDest) {
39 const char *abc = "abc";
40 char dest[7];
41
42 dest[0] = 'x';
43 dest[1] = 'y';
44 dest[2] = 'z';
45 dest[3] = '\0';
46
47 // Copy only part of the string onto the end
48 char *result = LIBC_NAMESPACE::strncat(dest, abc, 1);
49 ASSERT_EQ(dest, result);
50 ASSERT_STREQ(dest, "xyza");
51
52 // Copy a bit more, but without resetting.
53 result = LIBC_NAMESPACE::strncat(dest, abc, 2);
54 ASSERT_EQ(dest, result);
55 ASSERT_STREQ(dest, "xyzaab");
56
57 // Set just the end marker, to make sure it overwrites properly.
58 dest[3] = '\0';
59
60 result = LIBC_NAMESPACE::strncat(dest, abc, 3);
61 ASSERT_EQ(dest, result);
62 ASSERT_STREQ(dest, "xyzabc");
63
64 // Check that copying still works when count > src length
65 dest[0] = '\0';
66 // And that it doesn't write beyond what is necessary.
67 dest[4] = 'Z';
68 result = LIBC_NAMESPACE::strncat(dest, abc, 4);
69 ASSERT_EQ(dest, result);
70 ASSERT_STREQ(dest, "abc");
71 ASSERT_EQ(dest[4], 'Z');
72
73 result = LIBC_NAMESPACE::strncat(dest, abc, 5);
74 ASSERT_EQ(dest, result);
75 ASSERT_STREQ(dest, "abcabc");
76}
77

source code of libc/test/src/string/strncat_test.cpp