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 "utils/UnitTest/Test.h"
11 
12 TEST(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 = __llvm_libc::strncat(dest, abc, 0);
20   ASSERT_EQ(dest, result);
21   ASSERT_EQ(dest[0], '\0');
22 
23   // Then copy part of it.
24   result = __llvm_libc::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 = __llvm_libc::strncat(dest, abc, 3);
33   ASSERT_EQ(dest, result);
34   ASSERT_STREQ(dest, result);
35   ASSERT_STREQ(dest, abc);
36 }
37 
38 TEST(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 = __llvm_libc::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 = __llvm_libc::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 = __llvm_libc::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 = __llvm_libc::strncat(dest, abc, 4);
69   ASSERT_EQ(dest, result);
70   ASSERT_STREQ(dest, "abc");
71   ASSERT_EQ(dest[4], 'Z');
72 
73   result = __llvm_libc::strncat(dest, abc, 5);
74   ASSERT_EQ(dest, result);
75   ASSERT_STREQ(dest, "abcabc");
76 }
77