libc/test/src/string/strncat_test.cpp

   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
  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 = 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
  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 = 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 }