Function IsSubstringPred

tests/gtest/src/gtest.cc:1730–1734

// itself only.

bool IsSubstringPred(const char* needle, const char* haystack) {
  if (needle == nullptr || haystack == nullptr) return needle == haystack;

  return strstr(haystack, needle) != nullptr;
}

bool IsSubstringPred(const wchar_t* needle, const wchar_t* haystack) {
  if (needle == nullptr || haystack == nullptr) return needle == haystack;