libc/test/src/stdio/vsnprintf_test.cpp

   1 //===-- Unittests for snprintf --------------------------------------------===//
   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 // These tests are copies of the non-v variants of the printf functions. This is
  10 // because these functions are identical in every way except for how the varargs
  11 // are passed.
  12
  13 #include "src/stdio/vsnprintf.h"
  14
  15 #include "test/UnitTest/Test.h"
  16
  17 int call_vsnprintf(char *__restrict buffer, size_t buffsz,
  18                    const char *__restrict format, ...) {
  19   va_list vlist;
  20   va_start(vlist, format);
  21   int ret = LIBC_NAMESPACE::vsnprintf(buffer, buffsz, format, vlist);
  22   va_end(vlist);
  23   return ret;
  24 }
  25
  26 // The sprintf test cases cover testing the shared printf functionality, so
  27 // these tests will focus on snprintf exclusive features.
  28
  29 TEST(LlvmLibcVSNPrintfTest, CutOff) {
  30   char buff[100];
  31   int written;
  32
  33   written = call_vsnprintf(buff, 16, "A simple string with no conversions.");
  34   EXPECT_EQ(written, 36);
  35   ASSERT_STREQ(buff, "A simple string");
  36
  37   written = call_vsnprintf(buff, 5, "%s", "1234567890");
  38   EXPECT_EQ(written, 10);
  39   ASSERT_STREQ(buff, "1234");
  40
  41   written = call_vsnprintf(buff, 67, "%-101c", 'a');
  42   EXPECT_EQ(written, 101);
  43   ASSERT_STREQ(buff, "a "
  44                      "        " // Each of these is 8 spaces, and there are 8.
  45                      "        " // In total there are 65 spaces
  46                      "        " // 'a' + 65 spaces + '\0' = 67
  47                      "        "
  48                      "        "
  49                      "        "
  50                      "        "
  51                      "        ");
  52
  53   // passing null as the output pointer is allowed as long as buffsz is 0.
  54   written = call_vsnprintf(nullptr, 0, "%s and more", "1234567890");
  55   EXPECT_EQ(written, 19);
  56 }
  57
  58 TEST(LlvmLibcVSNPrintfTest, NoCutOff) {
  59   char buff[64];
  60   int written;
  61
  62   written = call_vsnprintf(buff, 37, "A simple string with no conversions.");
  63   EXPECT_EQ(written, 36);
  64   ASSERT_STREQ(buff, "A simple string with no conversions.");
  65
  66   written = call_vsnprintf(buff, 20, "%s", "1234567890");
  67   EXPECT_EQ(written, 10);
  68   ASSERT_STREQ(buff, "1234567890");
  69 }