libc/test/src/string/strstr_test.cpp

   1 //===-- Unittests for strstr ----------------------------------------------===//
   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/strstr.h"
  10 #include "test/UnitTest/Test.h"
  11
  12 TEST(LlvmLibcStrStrTest, NeedleNotInHaystack) {
  13   const char *haystack = "12345";
  14   const char *needle = "a";
  15   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), nullptr);
  16 }
  17
  18 TEST(LlvmLibcStrStrTest, NeedleIsEmptyString) {
  19   const char *haystack = "12345";
  20   const char *needle = "";
  21   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), haystack);
  22 }
  23
  24 TEST(LlvmLibcStrStrTest, HaystackIsEmptyString) {
  25   const char *haystack = "";
  26   const char *needle = "12345";
  27   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), nullptr);
  28 }
  29
  30 TEST(LlvmLibcStrStrTest, HaystackAndNeedleAreEmptyStrings) {
  31   const char *haystack = "";
  32   const char *needle = "";
  33   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), "");
  34 }
  35
  36 TEST(LlvmLibcStrStrTest, HaystackAndNeedleAreSingleCharacters) {
  37   const char *haystack = "a";
  38   // Same characer returns that character.
  39   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, /*needle=*/"a"), "a");
  40   // Different character returns nullptr.
  41   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, /*needle=*/"b"), nullptr);
  42 }
  43
  44 TEST(LlvmLibcStrStrTest, NeedleEqualToHaystack) {
  45   const char *haystack = "12345";
  46   const char *needle = "12345";
  47   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), "12345");
  48 }
  49
  50 TEST(LlvmLibcStrStrTest, NeedleSmallerThanHaystack) {
  51   const char *haystack = "12345";
  52   const char *needle = "345";
  53   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), "345");
  54 }
  55
  56 TEST(LlvmLibcStrStrTest, NeedleLargerThanHaystack) {
  57   const char *haystack = "123";
  58   const char *needle = "12345";
  59   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), nullptr);
  60 }
  61
  62 TEST(LlvmLibcStrStrTest, NeedleAtBeginning) {
  63   const char *haystack = "12345";
  64   const char *needle = "12";
  65   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), "12345");
  66 }
  67
  68 TEST(LlvmLibcStrStrTest, NeedleInMiddle) {
  69   const char *haystack = "abcdefghi";
  70   const char *needle = "def";
  71   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), "defghi");
  72 }
  73
  74 TEST(LlvmLibcStrStrTest, NeedleDirectlyBeforeNullTerminator) {
  75   const char *haystack = "abcdefghi";
  76   const char *needle = "ghi";
  77   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), "ghi");
  78 }
  79
  80 TEST(LlvmLibcStrStrTest, NeedlePastNullTerminator) {
  81   const char haystack[5] = {'1', '2', '\0', '3', '4'};
  82   // Shouldn't find anything after the null terminator.
  83   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, /*needle=*/"3"), nullptr);
  84   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, /*needle=*/"4"), nullptr);
  85 }
  86
  87 TEST(LlvmLibcStrStrTest, PartialNeedle) {
  88   const char *haystack = "la_ap_lap";
  89   const char *needle = "lap";
  90   // Shouldn't find la or ap.
  91   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), "lap");
  92 }
  93
  94 TEST(LlvmLibcStrStrTest, MisspelledNeedle) {
  95   const char *haystack = "atalloftwocities...wait, tale";
  96   const char *needle = "tale";
  97   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), "tale");
  98 }
  99
 100 TEST(LlvmLibcStrStrTest, AnagramNeedle) {
 101   const char *haystack = "dgo_ogd_god_odg_gdo_dog";
 102   const char *needle = "dog";
 103   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, needle), "dog");
 104 }
 105
 106 TEST(LlvmLibcStrStrTest, MorphedNeedle) {
 107   // Changes a single letter in the needle to mismatch with the haystack.
 108   const char *haystack = "once upon a time";
 109   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, "time"), "time");
 110   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, "lime"), nullptr);
 111   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, "tome"), nullptr);
 112   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, "tire"), nullptr);
 113   ASSERT_STREQ(LIBC_NAMESPACE::strstr(haystack, "timo"), nullptr);
 114 }