libc/test/src/string/strcmp_test.cpp

   1 //===-- Unittests for strcmp ----------------------------------------------===//
   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/strcmp.h"
  10 #include "test/UnitTest/Test.h"
  11
  12 TEST(LlvmLibcStrCmpTest, EmptyStringsShouldReturnZero) {
  13   const char *s1 = "";
  14   const char *s2 = "";
  15   int result = LIBC_NAMESPACE::strcmp(s1, s2);
  16   ASSERT_EQ(result, 0);
  17
  18   // Verify operands reversed.
  19   result = LIBC_NAMESPACE::strcmp(s2, s1);
  20   ASSERT_EQ(result, 0);
  21 }
  22
  23 TEST(LlvmLibcStrCmpTest, EmptyStringShouldNotEqualNonEmptyString) {
  24   const char *empty = "";
  25   const char *s2 = "abc";
  26   int result = LIBC_NAMESPACE::strcmp(empty, s2);
  27   // This should be '\0' - 'a' = -97
  28   ASSERT_EQ(result, '\0' - 'a');
  29
  30   // Similar case if empty string is second argument.
  31   const char *s3 = "123";
  32   result = LIBC_NAMESPACE::strcmp(s3, empty);
  33   // This should be '1' - '\0' = 49
  34   ASSERT_EQ(result, '1' - '\0');
  35 }
  36
  37 TEST(LlvmLibcStrCmpTest, EqualStringsShouldReturnZero) {
  38   const char *s1 = "abc";
  39   const char *s2 = "abc";
  40   int result = LIBC_NAMESPACE::strcmp(s1, s2);
  41   ASSERT_EQ(result, 0);
  42
  43   // Verify operands reversed.
  44   result = LIBC_NAMESPACE::strcmp(s2, s1);
  45   ASSERT_EQ(result, 0);
  46 }
  47
  48 TEST(LlvmLibcStrCmpTest, ShouldReturnResultOfFirstDifference) {
  49   const char *s1 = "___B42__";
  50   const char *s2 = "___C55__";
  51   int result = LIBC_NAMESPACE::strcmp(s1, s2);
  52   // This should return 'B' - 'C' = -1.
  53   ASSERT_EQ(result, 'B' - 'C');
  54
  55   // Verify operands reversed.
  56   result = LIBC_NAMESPACE::strcmp(s2, s1);
  57   // This should return 'C' - 'B' = 1.
  58   ASSERT_EQ(result, 'C' - 'B');
  59 }
  60
  61 TEST(LlvmLibcStrCmpTest, CapitalizedLetterShouldNotBeEqual) {
  62   const char *s1 = "abcd";
  63   const char *s2 = "abCd";
  64   int result = LIBC_NAMESPACE::strcmp(s1, s2);
  65   // 'c' - 'C' = 32.
  66   ASSERT_EQ(result, 'c' - 'C');
  67
  68   // Verify operands reversed.
  69   result = LIBC_NAMESPACE::strcmp(s2, s1);
  70   // 'C' - 'c' = -32.
  71   ASSERT_EQ(result, 'C' - 'c');
  72 }
  73
  74 TEST(LlvmLibcStrCmpTest, UnequalLengthStringsShouldNotReturnZero) {
  75   const char *s1 = "abc";
  76   const char *s2 = "abcd";
  77   int result = LIBC_NAMESPACE::strcmp(s1, s2);
  78   // '\0' - 'd' = -100.
  79   ASSERT_EQ(result, -'\0' - 'd');
  80
  81   // Verify operands reversed.
  82   result = LIBC_NAMESPACE::strcmp(s2, s1);
  83   // 'd' - '\0' = 100.
  84   ASSERT_EQ(result, 'd' - '\0');
  85 }
  86
  87 TEST(LlvmLibcStrCmpTest, StringArgumentSwapChangesSign) {
  88   const char *a = "a";
  89   const char *b = "b";
  90   int result = LIBC_NAMESPACE::strcmp(b, a);
  91   // 'b' - 'a' = 1.
  92   ASSERT_EQ(result, 'b' - 'a');
  93
  94   result = LIBC_NAMESPACE::strcmp(a, b);
  95   // 'a' - 'b' = -1.
  96   ASSERT_EQ(result, 'a' - 'b');
  97 }
  98
  99 TEST(LlvmLibcStrCmpTest, Case) {
 100   const char *s1 = "aB";
 101   const char *s2 = "ab";
 102   int result = LIBC_NAMESPACE::strcmp(s1, s2);
 103   ASSERT_LT(result, 0);
 104
 105   // Verify operands reversed.
 106   result = LIBC_NAMESPACE::strcmp(s2, s1);
 107   ASSERT_GT(result, 0);
 108 }