libc/test/src/stdio/snprintf_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 #include "src/stdio/snprintf.h"
  10
  11 #include "test/UnitTest/Test.h"
  12
  13 // The sprintf test cases cover testing the shared printf functionality, so
  14 // these tests will focus on snprintf exclusive features.
  15
  16 TEST(LlvmLibcSNPrintfTest, CutOff) {
  17   char buff[100];
  18   int written;
  19
  20   written = LIBC_NAMESPACE::snprintf(buff, 16,
  21                                      "A simple string with no conversions.");
  22   EXPECT_EQ(written, 36);
  23   ASSERT_STREQ(buff, "A simple string");
  24
  25   written = LIBC_NAMESPACE::snprintf(buff, 5, "%s", "1234567890");
  26   EXPECT_EQ(written, 10);
  27   ASSERT_STREQ(buff, "1234");
  28
  29   written = LIBC_NAMESPACE::snprintf(buff, 67, "%-101c", 'a');
  30   EXPECT_EQ(written, 101);
  31   ASSERT_STREQ(buff, "a "
  32                      "        " // Each of these is 8 spaces, and there are 8.
  33                      "        " // In total there are 65 spaces
  34                      "        " // 'a' + 65 spaces + '\0' = 67
  35                      "        "
  36                      "        "
  37                      "        "
  38                      "        "
  39                      "        ");
  40
  41   // passing null as the output pointer is allowed as long as buffsz is 0.
  42   written = LIBC_NAMESPACE::snprintf(nullptr, 0, "%s and more", "1234567890");
  43   EXPECT_EQ(written, 19);
  44 }
  45
  46 TEST(LlvmLibcSNPrintfTest, NoCutOff) {
  47   char buff[64];
  48   int written;
  49
  50   written = LIBC_NAMESPACE::snprintf(buff, 37,
  51                                      "A simple string with no conversions.");
  52   EXPECT_EQ(written, 36);
  53   ASSERT_STREQ(buff, "A simple string with no conversions.");
  54
  55   written = LIBC_NAMESPACE::snprintf(buff, 20, "%s", "1234567890");
  56   EXPECT_EQ(written, 10);
  57   ASSERT_STREQ(buff, "1234567890");
  58 }